CLI Guide

Command History
Version Description
9.9(0.0) Introduced on the FN IOM.
9.2(0.0) Introduced on the 10/40GbE Switch IO Module.
Usage Information
This is enabled by default; that is, for all updates received from EBGP peers, BGP
ensures that the first AS of the first AS segment is always the AS of the peer. If not,
the update is dropped and a counter is incremented. To view the failed enforce-
first-as check counter, use the show ip bgp ipv6 unicast neighbors
command.
If you disable enforce-first-as, view it using the show ip protocols
command.
Related
Commands
show ip bgp ipv6 unicast neighbors — displays IPv6 routing information exchanged
by BGP neighbors.
show ip protocols — views information on routing protocols.
bgp fast-external-fallover
Enable the fast external fallover feature, which immediately resets the BGP session if a link to a directly
connected external peer fails.
Syntax
bgp fast-external-fallover
To disable fast external fallover, use the no bgp fast-external-fallover
command.
Defaults Enabled.
Command Modes ROUTER BGP
Supported Modes Full–Switch
Command History
Version Description
9.9(0.0) Introduced on the FN IOM.
9.2(0.0) Introduced on the MXL 10/40GbE Switch IO Module.
Usage Information The bgp fast-external-fallover command appears in the show config
command output.
bgp four-octet-as-support
Enable 4-byte support for the BGP process.
Syntax
bgp four-octet-as-support
IPv6 Border Gateway Protocol (IPv6 BGP)
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