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FRR: Invalid route in BGP causes update storm, memory leak, and failure of Zebra.
Open, Requires assessmentPublicBUG

Description

Misconfiguration of routing, say for example, with Router A being connected to a peering exchange, but Router A not having 'redistribute connected' configured in BGP, will end up with Router B having no path to the nexthop for those routes, as peering-exchanges generally do not publicly advertise their prefixes. This causes the routes learnt from the peering exchange to be invalid on Router B, which in turn seems to cause an update storm and results in all memory being quickly consumed by Zebra and it crashing.

Setting a static route for the prefix of the peering exchange toward Router A resolved the condition.

Details

Difficulty level
Unknown (require assessment)
Version
VyOS 1.2.4
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Unspecified (possibly destroys the router)

Event Timeline

bbabich created this task.Jan 5 2020, 8:09 AM
pasik added a subscriber: pasik.Jan 6 2020, 12:26 PM

@bbabich If router A and router B connected via iBGP you need use nexthop-self

set protocols bgp 65002 neighbor 10.0.0.1 address-family ipv4-unicast nexthop-self

It telling the internal peer (router B) to use that router (router A) as the next hop to get to the external source (IX).
Which router is crashing? Router A or router B?
Do you have logs or state of sessions and memory? Any useful information.
Are you using snmp to poll bgp?