Reference Guide

bgp enforce-first-as
Disable (or enable) enforce-first-as check for updates received from EBGP peers.
S4820T
Syntax
bgp enforce-first-as
To turn off the default, use the no bgp enforce-first-as command.
Defaults Enabled
Command Modes ROUTER BGP
Command History
This guide is platform-specific. For command information about other platforms, refer to the
relevant FTOS Command Line Reference Guide .
The following is a list of the FTOS version history for this command.
Version 8.3.19.0 Introduced on the S4820T.
Version 8.3.11.1 Introduced on the Z9000.
Version 8.3.7.0 Introduced on the S4810.
Version 7.8.1.0 Introduced on the S-Series.
Version 7.7.1.0 Introduced on the C-Series.
Version 7.4.1.0 Introduced.
Usage
Information
This command 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 increments. Use the show ip bgp neighbors command to
view the “failed enforce-first-as check” counter.
If you disable the enforce-first-as command, it can be viewed using the show ip
protocols
command.
Related
Commands
show ip bgp neighbors — views the information the BGP neighbors exchange.
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.
S4820T
Syntax
bgp fast-external-fallover
To disable fast external fallover, use the no bgp fast-external-fallover command.
Defaults Enabled
Command Modes ROUTER BGP
Command History
This guide is platform-specific. For command information about other platforms, refer to the
relevant FTOS Command Line Reference Guide .
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