neighbor enforce-first-as

Ensures that a device requires the first ASN listed in the AS_SEQUENCE field of an AS path-update message from eBGP neighbors to be the ASN of the neighbor that sent the update.
Syntax
neighbor { ip-address | ipv6-address | peer-group-name } enforce-first-as [ disable | enable ]
no neighbor { ip-address | ipv6-address | peer-group-name } enforce-first-as [ disable | enable ]
Parameters
ip-address
Specifies the IPv4 address of the neighbor.
ipv6-address
Specifies the IPv6 address of the neighbor.
peer-group-name
Specifies the peer group name configured by the neighbor peer-group-name command.
disable
Disables this feature.
enable
Enables this feature.
Modes

BGP configuration mode

Usage Guidelines

The no form of the command disables this requirement globally for the device.

Examples

The following example enables the enforce-first-as feature for a specified neighbor. 

device# configure terminal
device(config)# router bgp
device(config-bgp-router)# neighbor 10.11.12.13 enforce-first-as enable
Parent topic: Commands N