Description
This article describes diagnosis commands to troubleshoot BGP issues on FortiSwitch units
Scope
FortiSwitch OS 7.0 and up.
Solution
The following FortiSwitch diagnose commands can help with diagnosing most common BGP issues on FortiSwitch units.
get router info bgp summary<- EBGP peering between FortiSwitch and the other end is up.
get router info bgp neighbors <neighbor IP> advertised-routes <- Command to verify the routes FortiSwith is advertising to the other end.
get router info bgp neighbors <neighbor IP> received-routes <- Commands to verify routes that FortiSwitch is receiving from the BGP peer.
get router info bgp neighbors <neighbor IP> routes <- Shows only filtered(in) received routes. If received routes aren’t filtered, then the output of these commands will be same.
get router info routing-table bgp <- Check all BGP table.
get router info routing-table details // Check full FortiSwitch routing table.
Try to clear the route database from offending network prefix, neighbors or even all learned BGP networks
execute router clear bgp
all Clear all BGP peers. [Take 0-5 arg(s)]
as Clear BGP peer by AS number. [Take 0-6 arg(s)]
dampening Clear route flap dampening information. [Take 0-1 arg(s)]
external Clear all external peers. [Take 0-2 arg(s)]
flap-statistics Clear route flap statistics. [Take 0-1 arg(s)]
ip Clear BGP peer by IP address. [Take 0-6 arg(s)]
ipv6 Clear BGP peer by IPv6 address. [Take 0-6 arg(s)]
If behavior can be reproduced, it may be useful to gather detailed debug logs from the BGP daemon.
diagnose debug reset
diagnose debug enable
diagnose ip router bgp all enable
diagnose ip router bgp level info
Run these until enough data is gathered, or clear BGP routes again and wait until the issue can be reproduced again.
To stop debugging, run:
diagnose debug disable
Try to reproduce several times and compare outputs to find if there is a message pattern on those outputs.
If further support from TAC is required, open a new ticket and attach all outputs mentioned in this article, along with a network diagram from the intended topology, an explanation of the behavior observed, and attach all output from the complete FortiSwitch diagnose script gathered when the issue is present.
diagnose debug report
Be sure to try 2-3 times to reproduce the issue when debugging and include those trials on different files.
