We had a similar issue when we migrated to debain a while back; flapping sessions, weird timeouts, etc. Tweaking `net.ipv6.route.max_size' helped. Some clues:
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=861115#10 - https://bird.network.cz/pipermail/bird-users/2020-February/014270.html Regards, Honghao Zeng > On Mar 22, 2021, at 4:29 PM, Pavlo Astakhov <[email protected]> wrote: > > Hello, all > > I got a weird question. We recently migrated two our routers from CentOS 7 to > Debian 10, installed Bird, placed config files back - and since then we are > observing BGP flaps. > > Moreover, flaps are observed on IPv6 peers only: > > Name Proto Table State Since Info > device1 Device --- up 2021-03-18 15:42:27 > direct1 Direct --- up 2021-03-18 15:42:27 > kernel1 Kernel master4 up 2021-03-18 15:42:27 > kernel2 Kernel master6 up 2021-03-18 15:42:27 > static1 Static master4 up 2021-03-18 15:42:27 > static2 Static master6 up 2021-03-18 15:42:27 > UPLINK BGP --- up 2021-03-18 15:42:31 Established > UPLINKv6 BGP --- up 2021-03-22 21:11:12 Established > AR1 BGP --- up 2021-03-18 15:42:31 Established > AR1v6 BGP --- up 2021-03-19 23:42:55 Established > AR2 BGP --- up 2021-03-18 15:42:28 Established > AR2v6 BGP --- up 2021-03-20 15:37:38 Established > BR2 BGP --- up 2021-03-18 15:42:28 Established > BR2v6 BGP --- up 2021-03-21 11:03:33 Established > ospf4 OSPF master4 up 2021-03-18 15:42:27 Running > ospf6 OSPF master6 up 2021-03-18 15:42:27 Running > > Flaps are unregular, currently we saw no coincedences with anything. The > network is stable, our and peers configs were not changed, Bird version too > (2.0.7 on both CentOS and Debian). > > The only message about this in logs is hold-related: > > 2021-03-22 21:01:10 <WARN> Kernel dropped some netlink messages, will resync > on next scan. > 2021-03-22 21:04:33 <WARN> Kernel dropped some netlink messages, will resync > on next scan. > 2021-03-22 21:06:10 <WARN> Kernel dropped some netlink messages, will resync > on next scan. > 2021-03-22 21:10:12 <RMT> UPLINKv6: Error: Hold timer expired > 2021-03-22 21:10:13 <WARN> Kernel dropped some netlink messages, will resync > on next scan. > 2021-03-22 21:10:15 <WARN> Kernel dropped some netlink messages, will resync > on next scan. > 2021-03-22 21:10:16 <WARN> Kernel dropped some netlink messages, will resync > on next scan. > 2021-03-22 21:10:16 <WARN> Kernel dropped some netlink messages, will resync > on next scan. > > Could you please suggest some way to go except of returning to CentOS? > > Thank you in advance. > > --
