[FROG] /31s, scope link and FRR BGP
jwbensley at gmail.com
Sat Oct 13 06:36:42 EDT 2018
On 13 October 2018 09:19:48 BST, "Chris Malton (Delta V)" <chris at deltav-tech.co.uk> wrote:
>I have /31s from an upstream provider on v4. If I specify "scope link"
>in /etc/network/interfaces for these, FRR seemingly doesn't allow the
>address to be used for update-source.
>Minimal reproduction example (taken from one of my core routers):
>iface lo inet loopback
> up ip addr add 22.214.171.124/32 scope global dev lo
>iface ens4 inet static
> address 192.168.1.3/31
> scope link
>router bgp 65000
> neighbor 192.168.1.2 remote-as 65001
> neighbor 192.168.1.2 interface ens4
> neighbor 192.168.1.2 update-source 192.168.1.3
>What happens in this case, is that FRR sends updates from 172.16.0.2
>instead of 192.168.1.3 (despite being explicitly told otherwise!).
>Have I found a bug, or have I done something stupid?
>Thanks in advance.
Have you tried "nei X update-source ens4"? I always prefer that in case you ever re-IP the interface.
Also, when you say FRR sends the updates from 172.16.0.2, do you mean the TCP packets come from that IP, or that is the IP used as the router ID in the BGP UPDATE messages, or both?
What do you have for "bgp router-id", 172.16.0.2?
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