Static routes and BFD

[Ondrej Zajicek]

On Mon, Oct 31, 2016 at 09:44:25AM +0100, J. Kendzorra wrote:
> In can see in a tcpdump that both are sending "Down" messages back and
> forth:
> 
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on vlan11, link-type EN10MB (Ethernet), capture size 65535 bytes
> 02:35:17.378336 IP 192.168.1.1.15324 > 192.168.1.6.3784: BFDv1, Control,
> State Down, Flags: [none], length: 24
> 02:35:17.529751 IP 192.168.1.6.56135 > 192.168.1.1.3784: BFDv1, Control,
> State Down, Flags: [none], length: 24
> 
> ,-- This is what the logs say on 192.168.1.1:
> 2016-10-31 02:38:04 -0600 <TRACE> bfd1: Sending CTL to 192.168.1.6 [Down]
> 2016-10-31 02:38:04 -0600 <TRACE> bfd1: Sending CTL to 192.168.1.6 [Down]
> `--
> 
> ,-- This is what the logs say on 192.168.1.6:
> 2016-10-31 02:39:29 <TRACE> bfd1: Sending CTL to 192.168.1.1 [Down]
> 2016-10-31 02:39:29 <TRACE> bfd1: Sending CTL to 192.168.1.1 [Down]

So packets are sent in both directions, they can be observed by tcpdump,
but they are neither reported as received-accepted nor received-rejected
by receiving BIRDs.

Are there no errors in log messages (e.g. cannot open linstening socket
when BFD is started)?

Is there no other software listening on 3784 port (try netstat -apn --ip)?

How do you have configured BIRD logging, would it log warning / errors?

Could you try to use tcpdump -vv to see BFD packet content (discriminator
values)?

Is there no other factor like firewall, NAT?

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."
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