Hi all, 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): /e/n/i config: auto lo iface lo inet loopback up ip addr add 195.246.200.2/32 scope global dev lo auto ens4 iface ens4 inet static address 192.168.1.3/31 scope link FRR config: 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. Regards, Chris Malton -- Delta V Technologies Limited 03333 402 406 www.deltav-tech.co.uk Office: 17 Elm Close, Southampton, SO16 7DT Company No. 11006104 Registered in England and Wales
On 13 October 2018 09:19:48 BST, "Chris Malton (Delta V)" <chris@deltav-tech.co.uk> wrote:
Hi all,
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):
/e/n/i config:
auto lo iface lo inet loopback up ip addr add 195.246.200.2/32 scope global dev lo
auto ens4 iface ens4 inet static address 192.168.1.3/31 scope link
FRR config:
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.
Regards,
Chris Malton
Hi Chris, 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? Cheers, James.
Hi James, On 13/10/18 11:36, James Bensley wrote:
Hi Chris,
Have you tried "nei X update-source ens4"? I always prefer that in case you ever re-IP the interface. No, I've not - I'll give it a try. 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? TCP Packets come from that IP. What do you have for "bgp router-id", 172.16.0.2? Yes. Cheers, James.
This email has been scanned by the MailScanner e-mail security system.
Regards, Chris -- Delta V Technologies Limited 03333 402 406 www.deltav-tech.co.uk Office: 17 Elm Close, Southampton, SO16 7DT Company No. 11006104 Registered in England and Wales
Replying to myself here... but it turned out that I needed to set "broadcast 0.0.0.0" as well in /e/n/i as suggested by the debian-devel mailing list[1]. Now working as expected with that "magic" in /e/n/i - I'm not going to ask why.... Regards, Chris [1] https://lists.debian.org/debian-devel/2003/02/msg00432.html -- Delta V Technologies Limited 03333 402 406 www.deltav-tech.co.uk Office: 17 Elm Close, Southampton, SO16 7DT Company No. 11006104 Registered in England and Wales
participants (2)
-
Chris Malton (Delta V) -
James Bensley