Apparently there is an old bug in quagga that affects some setups (i.e. two routers, two providers and with ibgp between them) . Seems that quagga already patched this. The patch should be included in next VyOS update:
See more details and fix here:
https://lists.quagga.net/pipermail/quagga-dev/2017-September/033284.html
This patch should also be included in 1.2.x, as i have seem similar behaviour with nightly builds.
Here is patch:
diff --git a/bgpd/bgp_aspath.c b/bgpd/bgp_aspath.c
index b7af5e88..d813bfba 100644 --- a/bgpd/bgp_aspath.c +++ b/bgpd/bgp_aspath.c @@ -903,7 +903,7 @@ aspath_put (struct stream *s, struct aspath *as, int use32bit ) assegment_header_put (s, seg->type, AS_SEGMENT_MAX); assegment_data_put (s, seg->as, AS_SEGMENT_MAX, use32bit); written += AS_SEGMENT_MAX; - bytes += ASSEGMENT_SIZE (written, use32bit); + bytes += ASSEGMENT_SIZE (AS_SEGMENT_MAX, use32bit); } /* write the final segment, probably is also the first */
@dmbaturin @UnicronNL this one is simple, can you add this to both branches
No, I got the patch for this patch, how should I proceed? I have some sessions with this problem.
i still confuse how to patch it, please explain more. thanks
im using vyos in production, how to fix it first?
My solution for the router in production. Vyos
The proposed "maximum-paths" looks to set the maximum number of paths for equal cost routing and not limit the long AS path that causes the noted log entry. I used the following in a production network to work around the issue:
set policy as-path-list maxas-limit rule 10 action 'deny'
set policy as-path-list maxas-limit rule 10 regex '^([{},0-9]+ ){100}'
set policy as-path-list maxas-limit rule 20 action 'permit'
set policy as-path-list maxas-limit rule 20 regex '.*'
set policy route-map route-import description 'Routes learned from peers'
set policy route-map route-import rule 10 action 'permit'
set policy route-map route-import rule 10 match as-path 'maxas-limit'
set protocols bgp [ASNUM] neighbor [IPADDR] route-map import 'route-import'
This regex was taken from a post on the NANOG mailing list and adjusted for 100 total AS numbers in the path. Note that this is applied on all EBGP sessions where my routers might learn a "bad" route.