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Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Command Reference, 4.0
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About This Guide
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Using the Command Line Interface
- A through B Commands
- C Commands
- D through F Commands
- G through I Commands
- J through L Commands
- M through O Commands
- P though R Commands
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S Commands
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same-security-traffic -- show asdm sessions
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show asp drop -- show curpriv
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show debug -- show ipv6 traffic
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show isakmp sa -- show route
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show running-config -- show running-config isakmp
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show running-config logging -- show running-config vpn-sessiondb
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show service-policy -- show xlate
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shun -- sysopt uauth allow-http-cache
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- T through Z Commands
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Feedback
Table Of Contents
dhcprelay information trust-all
default through drop Commands
default (crl configure)
To return all CRL parameters to their system default values, use the default command in crl configure configuration mode. The crl configure configuration mode is accessible from the crypto ca trustpoint configuration mode. These parameters are used only when the LDAP server requires them.
default
Syntax Description
This command has no arguments or keywords.
Defaults
No default behaviors or values.
Command Modes
The following table shows the modes in which you can enter the command:
Crl configure configuration
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Command History
Usage Guidelines
Invocations of this command do not become part of the active configuration.
Examples
The following example enters ca-crl configuration mode, and returns CRL command values to their defaults:
hostname(config)# crypto ca trustpoint centralhostname(ca-trustpoint)# crl configurehostname(ca-crl)# defaulthostname(ca-crl)#Related Commands
crl configure
Enters crl configure configuration mode.
crypto ca trustpoint
Enters trustpoint configuration mode.
protocol ldap
Specifies LDAP as a retrieval method for CRLs.
default (time-range)
To restore default settings for the absolute and periodic commands, use the default command in time-range configuration mode.
default {absolute | periodic days-of-the-week time to [days-of-the-week] time}
Syntax Description
Defaults
There are no default settings for this command.
Command Modes
The following table shows the modes in which you can enter the command:
Time-range configuration
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Command History
Usage Guidelines
If the end days-of-the-week value is the same as the start value, you can omit them.
If a time-range command has both absolute and periodic values specified, then the periodic commands are evaluated only after the absolute start time is reached, and are not further evaluated after the absolute end time is reached.
The time-range feature relies on the system clock of the FWSM; however, the feature works best with NTP synchronization.
Examples
The following example shows how to restore the default behavior of the absolute keyword:
hostname(config-time-range)# default absoluteRelated Commands
default enrollment
To return all enrollment parameters to their system default values, use the default enrollment command in crypto ca trustpoint configuration mode.
default enrollment
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Crypto ca trustpoint configuration
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Command History
Usage Guidelines
Invocations of this command do not become part of the active configuration.
Examples
The following example enters crypto ca trustpoint configuration mode for trustpoint central, and returns all enrollment parameters to their default values within trustpoint central:
hostname(config)# crypto ca trustpoint centralhostname(ca-trustpoint)# default enrollmentRelated Commands
clear configure crypto ca trustpoint
Removes all trustpoints.
crl configure
Enters crl configuration mode.
crypto ca trustpoint
Enters trustpoint configuration mode.
default-domain
To set a default domain name for users of the group policy, use the default-domain command in group-policy configuration mode. To delete a domain name, use the no form of this command.
default-domain {value domain-name | none}
no default-domain [domain-name]
Syntax Description
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Group-policy configuration
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Command History
Usage Guidelines
You can use only alphanumeric characters, hyphens (-), and periods (.) in default domain names.
To delete all default domain names, use the no form of this command without arguments. This deletes all configured default domain names, including a null list created by issuing the default-domain none command.
To prevent users from inheriting a domain name, use the default-domain none command.
The FWSM passes the default domain name to the IPSec client to append to DNS queries that omit the domain field. This domain name applies only to tunneled packets. When there are no default domain names, users inherit the default domain name in the default group policy.
Examples
The following example shows how to set a default domain name of FirstDomain for the group policy named FirstGroup:
hostname(config)# group-policy FirstGroup attributeshostname(config-group-policy)# default-domain value FirstDomainRelated Commands
default-group-policy
To specify the set of attributes that the user inherits by default, use the default-group-policy command in tunnel-group general-attributes configuration mode. To eliminate a default group policy name, use the no form of this command.
default-group-policy group-name
no default-group-policy group-name
Syntax Description
Defaults
The default group name is DfltGrpPolicy.
Command Modes
The following table shows the modes in which you can enter the command:
Tunnel-group general attributes configuration
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Command History
Usage Guidelines
The default group policy DfltGrpPolicy comes with the initial configuration of the FWSM. You can apply this attribute to all tunnel-group types.
Examples
The following example entered in config-general configuration mode, specifies a set of attributes for users to inherit by default for an IPSec LAN-to-LAN tunnel group named standard-policy. This set of commands defines the accounting server, the authentication server, the authorization server and the address pools.
hostname(config)# tunnel-group standard-policy type ipsec-rahostname(config)# tunnel-group standard-policy general-attributeshostname(config-general)# default-group-policy first-policyhostname(config-general)# accounting-server-group aaa-server123hostname(config-general)# address-pool (inside) addrpool1 addrpool2 addrpool3hostname(config-general)# authentication-server-group aaa-server456hostname(config-general)# authorization-server-group aaa-server78hostname(config-general)#Related Commands
default-information (EIGRP)
To control the candidate default route information for the EIGRP routing process, use the default-information command in router configuration mode. To suppress EIGRP candidate default route information in incoming or outbound updates, use the no form of this command.
default-information {in | out} [acl-name]
no default-information {in | out}
Syntax Description
acl-name
(Optional) Named standard access list.
in
Configures EIGRP to accept exterior default routing information.
out
Configures EIGRP to advertise external routing information.
Defaults
Exterior routes are accepted and sent.
Command Modes
The following table shows the modes in which you can enter the command:
Router configuration
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Command History
Usage Guidelines
Only the no form of the command or default-information commands with an access list specified will appear in the running configuration because, by default, the candidate default routing information is accepted and sent. The no form of the command does not take an acl-name argument.
Examples
The following example disables the receipt of exterior or candidate default route information:
hostname(config)# router eigrp 100hostname(config-router)# no default-information inRelated Commands
router eigrp
Creates an EIGRP routing process and enters configuration mode for that process.
default-information originate
To generate a default external route into an OSPF routing domain, use the default-information originate command in router configuration mode. To disable this feature, use the no form of this command.
default-information originate [always] [metric value] [metric-type {1 | 2}] [route-map name]
no default-information originate [[always] [metric value] [metric-type {1 | 2}] [route-map name]]
Syntax Description
Defaults
The default values are as follows:
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Command Modes
The following table shows the modes in which you can enter the command:
Router configuration
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Command History
Usage Guidelines
Using the no form of this command with optional keywords and arguments only removes the optional information from the command. For example, entering no default-information originate metric 3 removes the metric 3 option from the command in the running configuration. To remove the complete command from the running configuration, use the no form of the command without any options: no default-information originate.
Examples
The following example shows how to use the default-information originate command with an optional metric and metric type:
hostname(config-router)# default-information originate always metric 3 metric-type 2hostname(config-router)#Related Commands
router ospf
Enters router configuration mode.
show running-config router
Displays the commands in the global router configuration.
default-metric
To specify the EIGRP metrics for redistributed routes, use the default-metric command in router configuration mode. To restore the default values, use the no form of this command.
default-metric bandwidth delay reliability loading mtu
no default-metric bandwidth delay reliability loading mtu
Syntax Description
Defaults
Only connected routes can be redistributed without a default metric. The metric of redistributed connected routes is set to 0.
Command Modes
The following table shows the modes in which you can enter the command:
Router configuration
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Command History
Usage Guidelines
You must use a default metric to redistribute a protocol into EIGRP unless you use the metric keyword and attributes in the redistribute command. Metric defaults have been carefully set to work for a wide variety of networks. Take great care when changing these values. Keeping the same metrics is supported only when you are redistributing from static routes.
Examples
The following example shows how the redistributed RIP route metrics are translated into EIGRP metrics with values as follows: bandwidth = 1000, delay = 100, reliability = 250, loading = 100, and MTU = 1500.
hostname(config)# router eigrp 100hostname(config-router)# network 172.16.0.0hostname(config-router)# redistribute riphostname(config-router)# default-metric 1000 100 250 100 1500Related Commands
router eigrp
Creates an EIGRP routing process and enters router configuration mode for that process.
redistribute (EIGRP)
Redistributes routes into the EIGRP routing process.
delay
To set a delay value for an interface, use the delay command in interface configuration mode. To restore the default delay value, use the no form of this command.
delay delay-time
no delay
Syntax Description
Defaults
The default delay depends upon the interface type. Use the show interface command to see the delay value for an interface.
Command Modes
The following table shows the modes in which you can enter the command:
Interface configuration
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Command History
Usage Guidelines
The value entered is in tens of microseconds. The delay value displayed in the show interface output is in microseconds.
Examples
The following example changes the delay on an interface from the default 1000 to 2000. Truncated show interface command output is included before and after the delay command to show how the command affects the delay values. The delay value is noted in the second line of the show interface output, after the DLY label.
Notice that the command entered to change the delay value to 2000 is delay 200, not delay 2000. This is because the value entered with the delay command is in tens of microseconds, and the show interface output displays microseconds.
hostname(config)# show interface outsideInterface Vlan20 "outside", is up, line protocol is upHardware is EtherSVI, BW Unknown Speed-Capability, DLY 10 usecMAC address 000f.23be.d980, MTU 1500IP address 20.1.1.1, subnet mask 255.255.255.0Traffic Statistics for "outside":0 packets input, 0 bytes0 packets output, 0 bytes0 packets droppedFWSM(config-if)#Related Commands
delete
To delete a file in the disk partition, use the delete command in privileged EXEC mode.
delete [/noconfirm] [/recursive] [disk:]filename
Syntax Description
Defaults
If you do not specify a directory, the directory is the current working directory by default.
Command Modes
The following table shows the modes in which you can enter the command:
Privileged EXEC
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Usage Guidelines
The file is deleted from the current working directory if a path is not specified. Wildcards are supported when deleting files. When deleting files, you are prompted with the filename and you must confirm the deletion.
The following example shows how to delete a file named test.cfg in the current working directory:
hostname# delete test.cfgRelated Commands
cd
Changes the current working directory to the one specified.
rmdir
Removes a file or directory.
show file
Displays the specified file.
deny
To deny traffic based on the application type, use the deny command in class configuration mode. You can access the class configuration mode by first entering the policy-map command. To remove the deny statement, use the no form of this command.
deny {all | protocol}
no deny {all | protocol}
Syntax Description
all
Specifies all protocols.
protocol
Specifies a specific protocol, by name or number. For a list of supported protocol names, use the deny ? command.
Defaults
By default, all protcols are permitted unless you specifically deny them.
Command Modes
The following table shows the modes in which you can enter the command:
Class configuration
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Command History
Usage Guidelines
The Programmable Intelligent Services Accelerator (PISA) on the switch can quickly determine the application type of a given flow by performing deep packet inspection. This determination can be made even if the traffic is not using standard ports. The FWSM can leverage the high-performance deep packet inspection of the PISA card so that it can permit or deny traffic based on the application type.
Unlike the FWSM inspection feature, which passes through the control plane path, traffic that the PISA tags using GRE can pass through the FWSM accelerated path. Another benefit of FWSM and PISA integration is to consolidate your security configuration on a single FWSM instead of having to configure multiple upstream switches with PISAs installed.
You might want to deny certain types of application traffic when you want to preserve bandwidth for critical application types. For example, you might deny the use of peer-to-peer (P2P) applications if they are affecting your other critical applications.
After you identify the traffic using the class-map command, enter the policy-map command to identify the actions associated with each class map. Enter the class command to identify the class map, and then enter the deny command (along with permit commands) to determine the traffic to deny.
You can combine permit and deny statements to narrow the traffic that you want denied. You must enter at least one deny command. Unlike access lists, which have an implicit deny at the end, PISA actions have an implicit permit at the end.
For example, to permit all traffic except for Skype, eDonkey, and Yahoo, enter the following commands:
hostname(config-pmap-c)# deny skypehostname(config-pmap-c)# deny yahoohostname(config-pmap-c)# deny eDonkeyThe following example denies all traffic except for Kazaa and eDonkey:
hostname(config-pmap-c)# deny allhostname(config-pmap-c)# permit kazaahostname(config-pmap-c)# permit eDonkeySee the Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide for detailed information about PISA integration, including essential information about configuring the switch to work with this feature.
Examples
The following is an example configuration for PISA integration:
hostname(config)# access-list BAD_APPS extended permit 10.1.1.0 255.255.255.0 10.2.1.0 255.255.255.0hostname(config)# class-map denied_appshostname(config-cmap)# description "Apps to be blocked"hostname(config-cmap)# match access-list BAD_APPShostname(config-cmap)# policy-map denied_apps_policyhostname(config-pmap)# class denied_appshostname(config-pmap-c)# deny skypehostname(config-pmap-c)# deny yahoohostname(config-pmap-c)# deny eDonkeyhostname(config-pmap-c)# service-policy denied_apps_policy insideRelated Commands
deny version
To deny a specific version of SNMP traffic, use the deny version command in snmp-map configuration mode, which is accessible by entering the snmp-map command from global configuration mode. To disable this command, use the no form of this command.
deny version version
no deny version version
Syntax Description
version
Specifies the version of SNMP traffic that the FWSM drops. The permitted values are 1, 2, 2c, and 3.
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
snmp-map configuration
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Command History
Usage Guidelines
Use the deny version command to restrict SNMP traffic to specific versions of SNMP. Earlier versions of SNMP were less secure, so restricting SNMP traffic to Version 2 may be specified by your security policy. You use the deny version command within an SNMP map, which you configure using the snmp-map command. After creating the SNMP map, you enable the map using the inspect snmp command and then apply it to one or more interfaces using the service-policy command.
Examples
The following example shows how to identify SNMP traffic, define a SNMP map, define a policy, and apply the policy to the outside interface:
hostname(config)# access-list snmp-acl permit tcp any any eq 161hostname(config)# access-list snmp-acl permit tcp any any eq 162hostname(config)# class-map snmp-porthostname(config-cmap)# match access-list snmp-aclhostname(config-cmap)# exithostname(config)# snmp-map inbound_snmphostname(config-snmp-map)# deny version 1hostname(config-snmp-map)# exithostname(config)# policy-map inbound_policyhostname(config-pmap)# class snmp-porthostname(config-pmap-c)# inspect snmp inbound_snmphostname(config-pmap-c)# exithostname(config-pmap)# exithostname(config)# service-policy inbound_policy interface outsideRelated Commands
description
To add a description for a named configuration unit (for example, for a context or for an object group), use the description command in various configuration modes. To remove the description, use the no form of this command. The description adds helpful notes in your configuration.
description text
no description
Syntax Description
Defaults
No default behavior or values.
Command Modes
This command is available in various configuration modes.
Command History
Examples
The following example adds a description to the "Administration" context configuration:
hostname(config)# context administratorhostname(config-ctx)# description This is the admin context.hostname(config-ctx)# allocate-interface vlan 100hostname(config-ctx)# allocate-interface vlan 200hostname(config-ctx)# config-url disk://admin.cfgRelated Commands
dhcpd address
To define the IP address pool used by the DHCP server, use the dhcpd address command in global configuration mode. To remove an existing DHCP address pool, use the no form of this command.
dhcpd address IP_address1[-IP_address2] interface_name
no dhcpd address interface_name
Syntax Description
interface_name
Interface the address pool is assigned to.
IP_address1
Start address of the DHCP address pool.
IP_address2
End address of the DHCP address pool.
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
1.1(1)
This command was introduced.
3.1(1)
This command was changed from dhcpd.
Usage Guidelines
The dhcpd address ip1[-ip2] interface_name command specifies the DHCP server address pool. The address pool of a FWSM DHCP server must be within the same subnet of the FWSM interface on which it is enabled, and you must specify the associated FWSM interface using interface_name.
The size of the address pool is limited to 256 addresses per pool on the FWSM. If the address pool range is larger than 253 addresses, the netmask of the FWSM interface cannot be a Class C address (for example, 255.255.255.0) and needs to be something larger, for example, 255.255.254.0.
DHCP clients must be physically connected to the subnet of the FWSM DCHP server interface.
The dhcpd address command cannot use interface names with a "-" (dash) character because the "-" character is interpreted as a range specifier instead of as part of the object name.
The no dhcpd address interface_name command removes the DHCP server address pool that you configured for the specified interface.
Refer to the Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide for information on how to implement the DHCP server feature into the FWSM.
Examples
The following example shows how to use the dhcpd address, dhcpd dns, and dhcpd enable interface_name commands to configure an address pool and DNS server for the DHCP clients on the dmz interface of the FWSM:
hostname(config)# dhcpd address 10.0.1.100-10.0.1.108 dmzhostname(config)# dhcpd dns 209.165.200.226hostname(config)# dhcpd enable dmzThe following example shows how to configure a DHCP server on the inside interface. It uses the dhcpd address command to assign a pool of 10 IP addresses to the DHCP server on that interface.
hostname(config)# dhcpd address 10.0.1.101-10.0.1.110 insidehostname(config)# dhcpd dns 198.162.1.2 198.162.1.3hostname(config)# dhcpd wins 198.162.1.4hostname(config)# dhcpd lease 3000hostname(config)# dhcpd ping_timeout 1000hostname(config)# dhcpd domain example.comhostname(config)# dhcpd enable insideRelated Commands
dhcpd dns
To define the DNS servers for DHCP clients, use the dhcpd dns command in global configuration mode. To clear defined servers, use the no form of this command.
dhcpd dns dnsip1 [dnsip2]
no dhcpd dns [dnsip1 [dnsip2]]
Syntax Description
dnsip1
IP address of the primary DNS server for the DHCP client.
dnsip2
(Optional) IP address of the alternate DNS server for the DHCP client.
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
1.1(1)
This command was introduced.
3.1(1)
This command was changed from dhcpd.
Usage Guidelines
The dhcpd dns command lets you specify the IP address or addresses of the DNS server(s) for the DHCP client. You can specify two DNS servers. The no dhcpd dns command lets you remove the DNS IP address(es) from the configuration.
Examples
The following example shows how to use the dhcpd address, dhcpd dns, and dhcpd enable interface_name commands to configure an address pool and DNS server for the DHCP clients on the dmz interface of the FWSM.
hostname(config)# dhcpd address 10.0.1.100-10.0.1.108 dmzhostname(config)# dhcpd dns 192.168.1.2hostname(config)# dhcpd enable dmzRelated Commands
dhcpd domain
To define the DNS domain name for DHCP clients, use the dhcpd domain command in global configuration mode. To clear the DNS domain name, use the no form of this command.
dhcpd domain domain_name
no dhcpd domain [domain_name]
Syntax Description
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
1.1(1)
This command was introduced.
3.1(1)
This command was changed from dhcpd.
Usage Guidelines
The dhcpd domain command lets you specify the DNS domain name for the DHCP client. The no dhcpd domain command lets you remove the DNS domain server from the configuration.
Examples
The following example shows how to use the dhcpd domain command to configure the domain name supplied to DHCP clients by the DHCP server on the FWSM:
hostname(config)# dhcpd address 10.0.1.101-10.0.1.110 insidehostname(config)# dhcpd dns 198.162.1.2 198.162.1.3hostname(config)# dhcpd wins 198.162.1.4hostname(config)# dhcpd lease 3000hostname(config)# dhcpd ping_timeout 1000hostname(config)# dhcpd domain example.comhostname(config)# dhcpd enable insideRelated Commands
clear configure dhcpd
Removes all DHCP server settings.
show running-config dhcpd
Displays the current DHCP server configuration.
dhcpd enable
To enable the DHCP server, use the dhcpd enable command in global configuration mode. To disable the DHCP server, use the no form of this command.
dhcpd enable interface
no dhcpd enable interface
Syntax Description
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
1.1(1)
This command was introduced.
3.1(1)
This command was changed from dhcpd.
Usage Guidelines
The DHCP server provides network configuration parameters to DHCP clients. Support for the DHCP server within the FWSM means that the FWSM can use DHCP to configure connected clients.
The dhcpd enable interface command lets you enable the DHCP daemon to listen for the DHCP client requests on the DHCP-enabled interface. The no dhcpd enable command disables the DHCP server feature on the specified interface.
Note
When the FWSM responds to a DHCP client request, it uses the IP address and subnet mask of the interface where the request was received as the IP address and subnet mask of the default gateway in the response.
Note
Refer to the Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide for information on how to implement the DHCP server feature into the FWSM.
Examples
The following example shows how to use the dhcpd enable command to enable the DHCP server on the inside interface:
hostname(config)# dhcpd address 10.0.1.101-10.0.1.110 insidehostname(config)# dhcpd dns 198.162.1.2 198.162.1.3hostname(config)# dhcpd wins 198.162.1.4hostname(config)# dhcpd lease 3000hostname(config)# dhcpd ping_timeout 1000hostname(config)# dhcpd domain example.comhostname(config)# dhcpd enable insideRelated Commands
dhcpd lease
To specify the DHCP lease length, use the dhcpd lease command in global configuration mode. To restore the default value for the lease, use the no form of this command.
dhcpd lease lease_length
no dhcpd lease [lease_length]
Syntax Description
lease_length
Length of the IP address lease, in seconds, granted to the DHCP client from the DHCP server; valid values are from 300 to 1048575 seconds.
Defaults
The default lease_length is 3600 seconds.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
1.1(1)
This command was introduced.
3.1(1)
This command was changed from dhcpd.
Usage Guidelines
The dhcpd lease command lets you specify the length of the lease, in seconds, that is granted to the DHCP client. This lease indicates how long the DHCP client can use the assigned IP address that the DHCP server granted.
The no dhcpd lease command lets you remove the lease length that you specified from the configuration and replaces this value with the default value of 3600 seconds.
Examples
The following example shows how to use the dhcpd lease command to specify the length of the lease of DHCP information for DHCP clients:
hostname(config)# dhcpd address 10.0.1.101-10.0.1.110 insidehostname(config)# dhcpd dns 198.162.1.2 198.162.1.3hostname(config)# dhcpd wins 198.162.1.4hostname(config)# dhcpd lease 3000hostname(config)# dhcpd ping_timeout 1000hostname(config)# dhcpd domain example.comhostname(config)# dhcpd enable insideRelated Commands
clear configure dhcpd
Removes all DHCP server settings.
show running-config dhcpd
Displays the current DHCP server configuration.
dhcpd option
To configure DHCP options, use the dhcpd option command in global configuration mode. To clear the option, use the no form of this command. You can use the dhcpd option command to provide TFTP server information to Cisco IP Phones and routers.
dhcpd option code {ascii string} | {ip IP_address [IP_address]} | {hex hex_string}
no dhcpd option code
Syntax Description
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
1.1(1)
This command was introduced.
3.1(1)
This command was changed from dhcpd.
Usage Guidelines
When a DHCP option request arrives at the FWSM DHCP server, the FWSM places the value or values that are specified by the dhcpd option command in the response to the client.
The dhcpd option 66 and dhcpd option 150 commands specify TFTP servers that Cisco IP Phones and routers can use to download configuration files. Use the commands as follows:
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Note
Use the following guidelines when specifying an IP address for the dhcpd option 66 | 150 commands:
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For information about other DHCP options, refer to RFC 2132.
Note
You cannot configure the following DHCP options with the dhcpd option command:
Examples
The following example shows how to specify a TFTP server for DHCP option 66:
hostname(config)# dhcpd option 66 ascii MyTftpServerRelated Commands
clear configure dhcpd
Removes all DHCP server settings.
show running-config dhcpd
Displays the current DHCP server configuration.
dhcpd ping-timeout
To change the default timeout for DHCP ping, use the dhcpd ping-timeout command in global configuration mode. To return to the default value, use the no form of this command. To avoid address conflicts, the DHCP server sends two ICMP ping packets to an address before assigning that address to a DHCP client. This command specifies the ping timeout in milliseconds.
dhcpd ping-timeout number
no dhcpd ping-timeout
Syntax Description
number
The timeout value of the ping, in milliseconds. The minimum value is 10, the maximum is 10000. The default is 50.
Defaults
The default number of milliseconds for number is 50.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
1.1(1)
This command was introduced.
3.1(1)
This command was changed from dhcpd.
Usage Guidelines
The FWSM waits for both ICMP ping packets to time out before assigning an IP address to a DHCP client. For example, if the default value is used, the FWSM waits for 1500 milliseconds (750 milliseconds for each ICMP ping packet) before assigning an IP address.
A long ping timeout value can adversely affect the performance of the DHCP server.
Examples
The following example shows how to use the dhcpd ping-timeout command to change the ping timeout value for the DHCP server:
hostname(config)# dhcpd address 10.0.1.101-10.0.1.110 insidehostname(config)# dhcpd dns 198.162.1.2 198.162.1.3hostname(config)# dhcpd wins 198.162.1.4hostname(config)# dhcpd lease 3000hostname(config)# dhcpd ping-timeout 1000hostname(config)# dhcpd domain example.comhostname(config)# dhcpd enable insideRelated Commands
clear configure dhcpd
Removes all DHCP server settings.
show running-config dhcpd
Displays the current DHCP server configuration.
dhcpd wins
To define the WINS servers for DHCP clients, use the dhcpd wins command in global configuration mode. To remove the WINS servers from the DHCP server, use the no form of this command.
dhcpd wins server1 [server2]
no dhcpd wins [server1 [server2]]
Syntax Description
server1
Specifies the IP address of the primary Microsoft NetBIOS name server (WINS server).
server2
(Optional) Specifies the IP address of the alternate Microsoft NetBIOS name server (WINS server).
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
1.1(1)
This command was introduced.
3.1(1)
This command was changed from dhcpd.
Usage Guidelines
The dhcpd wins command lets you specify the addresses of the WINS servers for the DHCP client. The no dhcpd wins command removes the WINS server IP addresses from the configuration.
Examples
The following example shows how to use the dhcpd wins command to specify WINS server information that is sent to DHCP clients:
hostname(config)# dhcpd address 10.0.1.101-10.0.1.110 insidehostname(config)# dhcpd dns 198.162.1.2 198.162.1.3hostname(config)# dhcpd wins 198.162.1.4hostname(config)# dhcpd lease 3000hostname(config)# dhcpd ping_timeout 1000hostname(config)# dhcpd domain example.comhostname(config)# dhcpd enable insideRelated Commands
dhcp-network-scope
To specify the range of IP addresses the FWSM DHCP server should use to assign addresses to users of this group policy, use the dhcp-network-scope command in group-policy configuration mode. To remove the attribute from the running configuration, use the no form of this command. This option allows inheritance of a value from another group policy. To prevent inheriting a value, use the dhcp-network-scope none command.
dhcp-network-scope {ip_address} | none
no dhcp-network-scope
Syntax Description
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Group-policy configuration
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Command History
Examples
The following example shows how to set an IP subnetwork of 10.10.85.0 for the group policy named FirstGroup:
hostname(config)# group-policy FirstGroup attributeshostname(config-group-policy)# dhcp-network-scope 10.10.85.0dhcprelay enable
To enable the DHCP relay agent, use the dhcprelay enable command in global configuration mode. To disable DHCP relay agent, use the no form of this command. The DHCP relay agent allows DHCP requests to be forwarded from a specified FWSM interface to a specified DHCP server.
dhcprelay enable interface_name
no dhcprelay enable interface_name
Syntax Description
Defaults
The DHCP relay agent is disabled.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
2.2(1)
This command was introduced.
3.1(1)
This command was changed from dhcprelay.
Usage Guidelines
For the FWSM to start the DHCP relay agent with the dhcprelay enable interface_name command, you must have a dhcprelay server command already in the configuration. Otherwise, the FWSM displays an error message similar to the following:
DHCPRA: Warning - There are no DHCP servers configured!No relaying can be done without a server!Use the 'dhcprelay server <server_ip> <server_interface>' commandYou cannot enable DHCP relay under the following conditions:
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The no dhcprelay enable interface_name command removes the DHCP relay agent configuration for the interface that is specified by interface_name only.
Examples
The following example shows how to configure the DHCP relay agent for a DHCP server with an IP address of 10.1.1.1 on the outside interface of the FWSM, client requests on the inside interface of the FWSM, and a timeout value up to 90 seconds:
hostname(config)# dhcprelay server 10.1.1.1 outsidehostname(config)# dhcprelay timeout 90hostname(config)# dhcprelay enable insidehostname(config)# show running-config dhcprelaydhcprelay server 10.1.1.1 outsidedhcprelay enable insidedhcprelay timeout 90The following example shows how to disable the DHCP relay agent:
hostname(config)# no dhcprelay enable insidehostname(config)# show running-config dhcprelaydhcprelay server 10.1.1.1 outsidedhcprelay timeout 90Related Commands
dhcprelay information trust
You can preserve option 82 and forward a packet by identifying an interface as a trusted interface thus ensuring that DHCP snooping and IP source guard features on the switch work along with the FWSM.
You can enable this feature on interfaces configured with IPv4 and IPv6 addresses.
To configure a particular interface as a trusted interface that preserves option 82, enter the following command:
dhcprelay information trusted
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Priveleged EXEC
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Command History
Usage Guidelines
The interface-specific trusted configuration and global trusted configuration can exist together. For example there are three interfaces A, B and C, and a user configures interface A as trusted using the interface-specific command.Then the user configures the global command also.
Now all the three interfaces A, B, and C are trusted interfaces. If you enter the no dhcprelay information trust-all command, then interfaces B and C will become non-trusted interfaces. Interface A will continue to be a trusted interface, since the interface-specific trusted configuration is not removed.
Examples
The following example enables a particular interface as a trusted interface:
hostname(config)# dhcprelay information trustedRelated Commands
dhcprelay information trust-all
dhcprelay information trust-all
You can preserve option 82 and forward packets by identifying all the interfaces as trusted interfaces and ensuring that DHCP snooping and IP source guard features on the switch work along with the FWSM.
You can enable this feature on interfaces configured with IPv4 and IPv6 addresses.
To configure all interfaces as trusted interfaces, enter the following command:
dhcprelay information trust-all
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
Usage Guidelines
The interface-specific trusted configuration and global trusted configuration can exist together. For example there are three interfaces A, B and C, and a user configures interface A as trusted using the interface-specific command.Then the user configures the global command also.
Now all the three interfaces A, B, and C are trusted interfaces. If you enter the no dhcprelay information trust-all command, then interfaces B and C will become non-trusted interfaces. Interface A will continue to be a trusted interface, since the interface-specific trusted configuration is not removed.
Examples
The following example enables all interfaces except the interfaces that are shared or configured for the DHCP server:
hostname(config)# dhcprelay information trust-allRelated Commands
dhcprelay information trusted
dhcprelay server
To specify the DHCP server that DHCP requests are forwarded to, use the dhcpreplay server command in global configuration mode. To remove the DHCP server from the DHCP relay configuration, use the no form of this command. The DHCP relay agent allows DHCP requests to be forwarded from a specified FWSM interface to a specified DHCP server.
dhcprelay server IP_address interface_name
no dhcprelay server IP_address [interface_name]
Syntax Description
interface_name
Name of the FWSM interface on which the DHCP server resides.
IP_address
The IP address of the DHCP server to which the DHCP relay agent forwards client DHCP requests.
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
2.2(1)
This command was introduced.
3.1(1)
This command was changed from dhcprelay.
Usage Guidelines
You can add up to four DHCP relay servers per interface; however, there is a limit of ten DHCP relay servers total that can be configured on the FWSM. You must add at least one dhcprelay server command to the FWSM configuration before you can enter the dhcprelay enable command. You cannot configure a DHCP client on an interface that has a DHCP relay server configured.
The dhcprelay server command opens UDP port 67 on the specified interface and starts the DHCP relay task as soon as the dhcprelay enable command is added to the configuration. If there is no dhcprelay enable command in the configuration, then the sockets are not opened and the DHCP relay task does not start.
When you use the no dhcprelay server IP_address [interface_name] command, the interface stops forwarding DHCP packets to that server.
The no dhcprelay server IP_address [interface_name] command removes the DHCP relay agent configuration for the DHCP server that is specified by IP_address [interface_name] only.
Examples
The following example shows how to configure the DHCP relay agent for a DHCP server with an IP address of 10.1.1.1 on the outside interface of the FWSM, client requests on the inside interface of the FWSM, and a timeout value up to 90 seconds:
hostname(config)# dhcprelay server 10.1.1.1 outsidehostname(config)# dhcprelay timeout 90hostname(config)# dhcprelay enable insidehostname(config)# show running-config dhcprelaydhcprelay server 10.1.1.1 outsidedhcprelay enable insidedhcprelay timeout 90Related Commands
dhcprelay setroute
To set the default gateway address in the DHCP reply, use the dhcprelay setroute command in global configuration mode. To remove the default router, use the no form of this command. This command causes the default IP address of the DHCP reply to be substituted with the address of the specified FWSM interface.
dhcprelay setroute interface
no dhcprelay setroute interface
Syntax Description
interface
Configures the DHCP relay agent to change the first default IP address (in the packet sent from the DHCP server) to the address of interface.
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
2.2(1)
This command was introduced.
3.1(1)
This command was changed from dhcprelay.
Usage Guidelines
The dhcprelay setroute interface command lets you enable the DHCP relay agent to change the first default router address (in the packet sent from the DHCP server) to the address of interface.
If there is no default router option in the packet, the FWSM adds one containing the address of interface. This action allows the client to set its default route to point to the FWSM.
When you do not configure the dhcprelay setroute interface command (and there is a default router option in the packet), it passes through the FWSM with the router address unaltered.
Examples
The following example shows how to use the dhcprelay setroute command to set the default gateway in the DHCP reply from the external DHCP server to the inside interface of the FWSM:
hostname(config)# dhcprelay server 10.1.1.1 outsidehostname(config)# dhcprelay timeout 90hostname(config)# dhcprelay setroute insidehostname(config)# dhcprelay enable insideRelated Commands
dhcprelay timeout
To set the DHCP relay agent timeout value, use the dhcprelay timeout command in global configuration mode. To restore the timeout value to its default value, use the no form of this command.
dhcprelay timeout seconds
no dhcprelay timeout
Syntax Description
Defaults
The default value for the dhcprelay timeout is 60 seconds.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
2.2(1)
This command was introduced.
3.1(1)
This command was changed from dhcprelay.
Usage Guidelines
The dhcprelay timeout command lets you set the amount of time, in seconds, allowed for responses from the DHCP server to pass to the DHCP client through the relay binding structure.
Examples
The following example shows how to configure the DHCP relay agent for a DHCP server with an IP address of 10.1.1.1 on the outside interface of the FWSM, client requests on the inside interface of the FWSM, and a timeout value up to 90 seconds:
hostname(config)# dhcprelay server 10.1.1.1 outsidehostname(config)# dhcprelay timeout 90hostname(config)# dhcprelay enable insidehostname(config)# show running-config dhcprelaydhcprelay server 10.1.1.1 outsidedhcprelay enable insidedhcprelay timeout 90Related Commands
dhcp-server
To configure support for DHCP servers that assign IP addresses to clients as a VPN tunnel is established, use the dhcp-server command in tunnel-group general-attributes configuration mode. To return this command to the default, use the no form of this command.
dhcp-server hostname1 [...hostname10]
no dhcp-server hostname
Syntax Description
hostname1 ...hostname10
Specifies the IP address of the DHCP server. You can specify up to 10 DHCP servers.
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Tunnel-group general attributes configuration
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Command History
Usage Guidelines
In interface level, enter the dhcp-server <ip_address> command. There is no need to add <interface> in the command.
You can apply this attribute to IPSec remote access tunnel-group types only.
Examples
The following command entered in config-general configuration mode, adds three DHCP servers (dhcp1, dhcp2, and dhcp3) to the IPSec remote-access tunnel group remotegrp:
hostname(config)# tunnel-group remotegrp type ipsec_rahostname(config)# tunnel-group remotegrp generalhostname(config-general)# default-group-policy remotegrphostname(config-general)# dhcp-server dhcp1 dhcp2 dhcp3hostname(config-general)Related Commands
dir
To display the directory contents, use the dir command in privileged EXEC mode.
dir [/all] [all-filesystems] [/recursive] [flash: | system:] [path]
Syntax Description
Defaults
If you do not specify a directory, the directory is the current working directory by default.
Command Modes
The following table shows the modes in which you can enter the command:
Privileged EXEC
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Command History
Usage Guidelines
The dir command without keywords or arguments displays the directory contents of the current directory.
Examples
The following example shows how to display the directory contents:
hostname# dirDirectory of disk0:/1 -rw- 1519 10:03:50 Jul 14 2003 my_context.cfg2 -rw- 1516 10:04:02 Jul 14 2003 my_context.cfg3 -rw- 1516 10:01:34 Jul 14 2003 admin.cfg60985344 bytes total (60973056 bytes free)This example shows how to display recursively the contents of the entire file system:
hostname# dir /recursive disk0:Directory of disk0:/*1 -rw- 1519 10:03:50 Jul 14 2003 my_context.cfg2 -rw- 1516 10:04:02 Jul 14 2003 my_context.cfg3 -rw- 1516 10:01:34 Jul 14 2003 admin.cfg60985344 bytes total (60973056 bytes free)Related Commands
cd
Changes the current working directory to the one specified.
pwd
Displays the current working directory.
mkdir
Creates a directory.
rmdir
Removes a directory.
disable
To exit privileged EXEC mode and return to unprivileged EXEC mode, use the disable command in privileged EXEC mode.
disable
Syntax Description
This command has no arguments or keywords.
Defaults
No default behaviors or values.
Command Modes
The following table shows the modes in which you can enter the command:
Privileged EXEC
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Command History
Usage Guidelines
Use the enable command to enter privileged EXEC mode. The disable command lets you exit privileged EXEC mode and returns you to user EXEC mode.
Examples
The following example shows how to enter privileged EXEC mode:
hostname>enablehostname#The following example shows how to exit privileged EXEC mode:
hostname#disablehostname>Related Commands
distance eigrp
To configure the administrative distances of internal and external EIGRP routes, use the distance eigrp command in router configuration mode. To restore the default values, use the no form of this command.
distance eigrp internal-distance external-distance
no distance eigrp
Syntax Description
Defaults
The default values are as follows:
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Command Modes
The following table shows the modes in which you can enter the command:
Router configuration
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Command History
Usage Guidelines
Because every routing protocol has metrics based on algorithms that are different from the other routing protocols, it is not always possible to determine the "best path" for two routes to the same destination that were generated by different routing protocols. Administrative distance is a route parameter that the FWSM uses to select the best path when there are two or more different routes to the same destination from two different routing protocols.
If you have more than one routing protocol running on the FWSM, you can use the distance eigrp command to adjust the default administrative distances of routes discovered by the EIGRP routing protocol in relation to the other routing protocols. Table 11-1 lists the default administrative distances for the routing protocols supported by the FWSM.
The no form of the command does not take any keywords or arguments. Using the no form of the command restores the default administrative distance for both internal and external EIGRP routes.
Examples
The following example uses the distance eigrp command set the administrative distance of all EIGRP internal routes to 80 and all EIGRP external routes to 115. Setting the EIGRP external route administrative distance to 115 would give routes discovered by EIGRP to a specific destination preference over the same routes discovered by RIP but not by OSPF.
hostname(config)# router eigrp 100hostname(config-router)# network 192.168.7.0hostname(config-router)# network 172.16.0.0hostname(config-router)# distance eigrp 90 115Related Commands
router eigrp
Creates an EIGRP routing process and enters configuration mode for that process.
distance ospf
To define OSPF route administrative distances based on route type, use the distance ospf command in router configuration mode. To restore the default values, use the no form of this command.
distance ospf [intra-area d1] [inter-area d2] [external d3]
no distance ospf
Syntax Description
Defaults
The default values for d1, d2, and d3 are 110.
Command Modes
The following table shows the modes in which you can enter the command:
Router configuration
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Command History
Usage Guidelines
You must specify at least one keyword and argument. You can enter the commands for each type of administrative distance separately, however they appear as a single command in the configuration. If you reenter an administrative distance, the administrative distance for only that route type changes; the administrative distances for any other route types remain unaffected.
The no form of the command does not take any keywords or arguments. Using the no form of the command restores the default administrative distance for all of the route types. If you want to restore the default administrative distance for a single route type when you have multiple route types configured, you can do one of the following:
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Examples
The following example sets the administrative distance of external routes to 150:
hostname(config-router)# distance ospf external 105hostname(config-router)#The following example shows how entering separate commands for each route type appears as a single command in the router configuration:
hostname(config-router)# distance ospf intra-area 105 inter-area 105hostname(config-router)# distance ospf intra-area 105hostname(config-router)# distance ospf external 105hostname(config-router)# exithostname(config)# show running-config router ospf 1!router ospf 1distance ospf intra-area 105 inter-area 105 external 105!hostname(config)#The following example shows how to set each administrative distance to 105, and then change only the external administrative distance to 150. The show running-config router ospf command shows how only the external route type value changed, while the other route types retained the value previously set.
hostname(config-router)# distance ospf external 105 intra-area 105 inter-area 105hostname(config-router)# distance ospf external 150hostname(config-router)# exithostname(config)# show running-config router ospf 1!router ospf 1distance ospf intra-area 105 inter-area 105 external 150!hostname(config)#Related Commands
router ospf
Enters router configuration mode.
show running-config router
Displays the commands in the global router configuration.
distribute-list in
To filter the networks received in routing updates, use the distribute-list in command in router configuration mode. To remove the filtering, use the no form of this command.
distribute-list acl in [interface if_name]
no distribute-list acl in [interface if_name]
Syntax Description
Defaults
Networks are not filtered in incoming updates.
Command Modes
The following table shows the modes in which you can enter the command:
Router configuration
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Command History
Usage Guidelines
If no interface is specified, the access list will be applied to all incoming updates.
Examples
The following example filters EIGRP routing updates received on the outside interface. It accepts routes in the 10.0.0.0 network and discards all others.
hostname(config)# access-list eigrp_filter permit 10.0.0.0hostname(config)# access-list eigrp_filter deny anyhostname(config)# router eigrp 100hostname(config-router)# network 10.0.0.0hostname(config-router)# distribute-list eigrp_filter in interface outsideRelated Commands
distribute-list out
To filter specific networks from being sent in routing updates, use the distribute-list out command in router configuration mode. To remove the filtering, use the no form of this command.
distribute-list acl out [interface if_name | ospf pid | static | connected]
no distribute-list acl out [interface if_name | ospf pid | static | connected]
Syntax Description
Defaults
Networks are not filtered in sent updates.
Command Modes
The following table shows the modes in which you can enter the command:
Router configuration
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Command History
Usage Guidelines
If no interface is specified, the access list will be applied to all outgoing updates.
Note
Examples
The following example would cause only one network to be advertised by a RIP routing process, network 10.108.0.0:
hostname(config)# access-list 1 permit 10.108.0.0hostname(config)# access-list 1 deny 0.0.0.0 255.255.255.255hostname(config)# router riphostname(config-router)# network 10.108.0.0hostname(config-router)# distribute-list 1 outRelated Commands
dns domain-lookup
To enable the FWSM to send DNS requests to a DNS server to perform a name lookup for supported commands, use the dns domain-lookup command in global configuration mode. To disable DNS lookup, use the no form of this command.
dns domain-lookup interface_name
no dns domain-lookup interface_name
Syntax Description
Defaults
DNS lookup is disabled by default.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
Usage Guidelines
Use the dns name-server command to configure the DNS server addresses to which you want to send DNS requests. See the dns name-server command for a list of commands that support DNS lookup.
The FWSM maintains a cache of name resolutions that consists of dynamically learned entries. Instead of making queries to external DNS servers each time an hostname-to-IP-address translation is needed, the FWSM caches information returned from external DNS requests. The FWSM only makes requests for names that are not in the cache. The cache entries time out automatically according to the DNS record expiration, or after 72 hours, whichever comes first.
Examples
The following example enables DNS lookup on the inside interface:
hostname(config)# dns domain-lookup insideRelated Commands
dns name-server
To identify one or more DNS servers, use the dns name-server command in global configuration mode. To remove a server, use the no form of this command.
[no] dns name-server ip_address [ip_address2] [...] [ip_address6]
Syntax Description
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
Usage Guidelines
The FWSM uses DNS to resolve server names in your certificate configuration. Other features that define server names (such as AAA) do not support DNS resolution. You must enter the IP address or manually resolve the name to an IP address by using the name command.
To enable DNS lookup, configure the dns domain-lookup command. If you do not enable DNS lookup, the DNS servers are not used.
Commands that support DNS resolution include the following:
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You can manually enter names and IP addresses using the name command.
See the dns retries command to set how many times the FWSM tries the list of DNS servers.
Examples
The following example shows how to add three DNS servers:
hostname(config)-if# dns name-server 10.1.1.1 10.2.3.4 192.168.5.5The following output shows how the FWSM saves the configuration as separate commands:
dns name-server 10.1.1.1dns name-server 10.2.3.4dns name-server 192.168.5.5The following example shows how to add two additional servers as one command:
hostname(config-if)# dns name-server 10.5.1.1 10.8.3.8hostname(config-if)# show running-config dnsdns name-server 10.1.1.1dns name-server 10.2.3.4dns name-server 192.168.5.5dns name-server 10.5.1.1dns name-server 10.8.3.8...The following example shows how to enter the servers using two commands:
hostname(config)# dns name-server 10.5.1.1hostname(config)# dns name-server 10.8.3.8The following example shows how to delete multiple servers using one command. You can also use multiple commands.
hostname(config)# no dns name-server 10.5.1.1 10.8.3.8Related Commands
dns retries
To specify the number of times to retry the list of DNS servers when the FWSM does not receive a response, use the dns retries command in global configuration mode. To restore the default setting, use the no form of this command.
dns retries number
no dns retries [number]
Syntax Description
Defaults
The default number of retries is 2.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
Usage Guidelines
Add DNS servers using the dns name-server command.
Examples
The following example sets the number of retries to 0. The FWSM only tries each server one time.
hostname(config)# dns retries 0Related Commands
dns timeout
To specify the amount of time to wait before trying the next DNS server, use the dns timeout command in global configuration mode. To restore the default timeout, use the no form of this command.
dns timeout seconds
no dns timeout [seconds]
Syntax Description
Defaults
The default timeout is 2 seconds.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
Examples
The following example sets the timeout to 1 second:
hostname(config)# dns timeout 1Related Commands
dns-guard
To <text>, use the dns-guard command in global configuration mode.
To <text about removing command>, use the no form of this command.
dns-guard
no dns-guard
Syntax Description
There are no arguments or keywords for this command.
Defaults
DNS Guard is enabled by default.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
Usage Guidelines
When a client sends a DNS request to an external DNS server, only the first response is accepted by the FWSM. All additional responses from other DNS servers are dropped by the FWSM.
After the client issues a DNS request, a dynamic hole allows UDP packets to return from the DNS server. When the FWSM receives a response from the first DNS server, the connection that was created in the accelerated path is dropped so that subsequent responses from other DNS servers are dropped by the FWSM. The UDP DNS connection is deleted immediately rather than marking the connection for deletion.
The FWSM creates a session-lookup key based on the source and destination IP address along with the protocol and the DNS ID instead of the source and destination ports.
If the DNS client and DNS server use TCP for DNS, the connection is cleared like a normal TCP connection.
However, if clients receive DNS responses from multiple DNS servers, you can disable the default DNS behavior on a per context basis. When DNS Guard is disabled, a response from the first DNS server does not delete the connection and the connection is treated as a normal UDP connection.
Examples
The following example shows the use of the dns-guard command to disable the DNS Guard feature:
hostname(config)# no dns-guardhostname(config)# show running-config | inc dns-guardno dns-guardhostname(config)#Related Commands
dns-server
To set the IP address of the primary and secondary DNS servers, use the dns-server command in group-policy mode. To remove the attribute from the running configuration, use the no form of this command. This option allows inheritance of a DNS server from another group policy. To prevent inheriting a server, use the dns-server none command.
dns-server {value ip_address [ip_address] | none}
no dns-server
Syntax Description
Defaults
No default behavior or values.
Command Modes
The following table shows the modes in which you can enter the command:
Group-policy configuration
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Command History
Usage Guidelines
Every time you issue the dns-server command you overwrite the existing setting. For example, if you configure DNS server x.x.x.x and then configure DNS server y.y.y.y, the second command overwrites the first, and y.y.y.y becomes the sole DNS server. The same holds true for multiple servers. To add a DNS server rather than overwrite previously configured servers, include the IP addresses of all DNS servers when you enter this command.
Examples
The following example shows how to configure DNS servers with the IP addresses 10.10.10.15, 10.10.10.30, and 10.10.10.45 for the group policy named FirstGroup.
hostname(config)# group-policy FirstGroup attributeshostname(config-group-policy)# dns-server value 10.10.10.15 10.10.10.30 10.10.10.45
domain-name
To set the default domain name, use the domain-name command in global configuration mode. To remove the domain name, use the no form of this command.
domain-name name
no domain-name [name]
Syntax Description
Defaults
The default domain name is default.domain.invalid.
Command Modes
The following table shows the modes in which you can enter the command:
Global configuration
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Command History
Usage Guidelines
The FWSM appends the domain name as a suffix to unqualified names. For example, if you set the domain name to "example.com," and specify a syslog server by the unqualified name of "jupiter," then the security appliance qualifies the name to "jupiter.example.com."
For multiple context mode, you can set the domain name for each context, as well as within the system execution space.
Examples
The following example sets the domain as example.com:
hostname(config)# domain-name example.comRelated Commands
drop (class)
To drop all packets that match the match command or class command, use the drop command in match or class configuration mode. You can access the match or class configuration mode by first entering the policy-map type inspect command. To disable this action, use the no form of this command.
drop [log]
no drop [log]
Syntax Description
Defaults
No default behaviors or values.
Command Modes
The following table shows the modes in which you can enter the command:
Match and class configuration
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Command History
Usage Guidelines
When using the Modular Policy Framework, drop packets that match a match command or class map by using the drop command in match or class configuration mode. This drop action is available in an inspection policy map (the policy-map type inspect command) for application traffic; however, not all applications allow this action.
An inspection policy map consists of one or more match and class commands. The exact commands available for an inspection policy map depends on the application. After you enter the match or class command to identify application traffic (the class command refers to an existing class-map type inspect command that in turn includes match commands), you can enter the drop command to drop all packets that match the match command or class command.
If you drop a packet, then no further actions are performed in the inspection policy map. For example, if the first action is to drop the packet, then it will never match any further match or class commands. If the first action is to log the packet, then a second action, such as dropping the packet, can occur. You can configure both the drop and the log action for the same match or class command, in which case the packet is logged before it is dropped for a given match.
When you enable application inspection using the inspect command in a Layer 3/4 policy map (the policy-map command), you can enable the inspection policy map that contains this action, for example, enter the inspect http http_policy_map command where http_policy_map is the name of the inspection policy map.
Examples
The following example drops packets and sends a log when they match the http-traffic class map. If the same packet also matches the second match command, it will not be processed because it was already dropped.
hostname(config-cmap)# policy-map type inspect http http-map1hostname(config-pmap)# class http-traffichostname(config-pmap-c)# drop loghostname(config-pmap-c)# match req-resp content-type mismatchhostname(config-pmap-c)# reset logRelated Commands
drop (gtp-map)
To drop specified GTP messages, use the drop command in gtp-map configuration mode. To remove the command, use the no form of this command.
drop {apn access_point_name | message message_id | version version}
no drop {apn access_point_name | message message_id | version version}
Syntax Description
Defaults
All messages with valid message IDs, APNs, and version are inspected.
Any APN is allowed.
Command Modes
The following table shows the modes in which you can enter the command:
Gtp-map configuration
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Command History
Usage Guidelines
Use the drop message command to drop specific GTP messages that you do not want to allow in your network.
Use the drop apn command to drop GTP messages with the specified access point. Use the drop version command to drop GTP messages with the specified version.
Examples
The following example drops traffic to message ID 20:
hostname(config)# gtp-map qtp-policyhostname(config-gtpmap)# drop message 20Related Commands
drop-connection
When using the Modular Policy Framework, drop packets and close the connection for traffic that matches a match command or class map by using the drop-connection command in match or class configuration mode. You can access the match or class configuration mode by first entering the policy-map type inspect command. To disable this action, use the no form of this command.
drop-connection [log]
no drop-connection [log]
Syntax Description
Defaults
No default behaviors or values.
Command Modes
The following table shows the modes in which you can enter the command:
Match and class configuration
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Command History
Usage Guidelines
The connection will be removed from the connection database on the FWSM. Any subsequent packets entering the FWSM for the dropped connection will be discarded. This drop-connection action is available in an inspection policy map for application traffic; however, not all applications allow this action.
An inspection policy map consists of one or more match and class commands. The exact commands available for an inspection policy map depends on the application. After you enter the match or class command to identify application traffic (the class command refers to an existing class-map type inspect command that in turn includes match commands), you can enter the drop-connection command to drop packets and close the connection for traffic that matches the match command or class command.
If you drop a packet or close a connection, then no further actions are performed in the inspection policy map. For example, if the first action is to drop the packet and close the connection, then it will never match any further match or class commands. If the first action is to log the packet, then a second action, such as dropping the packet, can occur. You can configure both the drop-connection and the log action for the same match or class command, in which case the packet is logged before it is dropped for a given match.
When you enable application inspection using the inspect command in a Layer 3/4 policy map (the policy-map command), you can enable the inspection policy map that contains this action, for example, enter the inspect http http_policy_map command where http_policy_map is the name of the inspection policy map.
Examples
The following example drops packets, closes the connection, and sends a log when they match the http-traffic class map. If the same packet also matches the second match command, it will not be processed because it was already dropped.
hostname(config-cmap)# policy-map type inspect http http-map1hostname(config-pmap)# class http-traffichostname(config-pmap-c)# drop-connection loghostname(config-pmap-c)# match req-resp content-type mismatchhostname(config-pmap-c)# reset logRelated Commands
