BIRD drops specific IPv6 session for no reason

[Tapio Haapala]

double check that your router have arp entry and route for that peer when that happens. Example if your router get wrong route for peer it can send response packets (or some cases arp requests) to wrong interface. So dump your another interfaces also at same time and you will see what it do. Probably watch for route and arp with proper grep and -n is also your friend if that happens very often. 

On 28/02/2020 13.41, Stavros Konstantaras wrote:
> Hi Bird community,
> 
> We are investigating a weird customer issue regarding our Bird Route Servers (version 1.6.3) and a specific IPv6 session. Customer reports a sudden drop of his IPv6 session and -until now- we could not relate those drops with any issue or instability. Everything seems normal and no other customer complained at the moment of the incident. 
> 
> 
> 
> After some packet capturing at the moment of the event, we discovered that BIRD does not send a response messages to the customer’s BGP keepalive messages (see attached picture), which result to the BGP hold timer to expire and the sessions to be dropped. We observed this anomaly with both RSs but at different time slots and the tcpdump capture was running at the Interface were Bird is sending all BGP traffic for customers. At the moment of the event, we didn’t do any maintenance or other RS related work.
> 
> Has any of you experienced this in the past? If yes, how did you solve this?
> Any related feedback is welcomed. 
> 
> 
> 
> 
> 
> 
> 
> Best regards,
> 
> Stavros Konstantaras | Sr. Network Engineer | AMS-IX 
> M +31 (0) 620 89 51 04 | T +31 20 305 8999
> ams-ix.net <http://ams-ix.net>
> 


-- 
F-Solutions Oy

Tapio Haapala

PL7, 90571 Oulu
GSM   +358400998371
Skype burner-
IRC   Burner at ircnet