Table Of Contents

Commonly Used Protocols in the Infrastructure

Commonly Used Protocols in the Infrastructure

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Table B-1 lists commonly used protocols found in the infrastructure.

Table B-1 Commonly Used Protocols in the Infrastructure

Protocol	Protocol Number, TCP/UDP Ports, Message Type
BGP	TCP/179
OSPF	Prot 89
EIGRP	Prot 88
GRE	Prot 47
AH	Prot 51
ESP	Prot 50
TACACS+	TCP/49
RADIUS	UDP/1812, UDP/1813; in the past UDP/1645 and UDP/1646
SSH	TCP/22
TELNET	TCP/23
SNMP	UDP/161
NTP	UDP/123
ICMP	Prot 1, ttl-exceeded, port-unreachable, echo, echo-reply
DNS	UDP/53