Hello K. Thanks for checking in this issue. But, I can't understand. If it was because of the iptables, it would have been a problem for BGP as well. And I'm not using iptables rules, So Any packets weren't dropped. * iptables status ============================================================ # iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination ============================================================ * Port status ============================================================ # netstat -lnp | grep bird tcp 0 0 0.0.0.0:179 0.0.0.0:* LISTEN 44890/bird udp 0 0 0.0.0.0:3784 0.0.0.0:* 44890/bird udp 0 0 0.0.0.0:4784 0.0.0.0:* 44890/bird unix 2 [ ACC ] STREAM LISTENING 320049 44890/bird /run/bird/bird.ctl unix 2 [ ACC ] STREAM LISTENING 398938 44893/bird6 /run/bird/bird6.ctl ============================================================ * BIRD Status ============================================================ # birdc show bfd sessions BIRD 1.6.8 ready. bfd1: IP address Interface State Since Interval Timeout 10.11.251.4 --- Init 09:37:57 2.000 6.000 10.11.250.4 --- Init 09:37:56 2.000 6.000 # birdc show protocols BIRD 1.6.8 ready. name proto table state since info kernel1 Kernel master up 09:37:52 direct1 Direct master up 09:37:52 device1 Device master up 09:37:52 static1 Static master up 09:37:52 bfd1 BFD master up 09:37:52 as1 BGP master up 09:37:56 Established as2 BGP master up 09:37:57 Established ============================================================ Is it related to the increase in this value? ============================================================ # netstat -s ... Udp: 52759 packets received 0 packets to unknown port received 0 packet receive errors 34365164 packets sent 0 receive buffer errors 0 send buffer errors IgnoredMulti: 3399 ... ============================================================ Please check it. Regards. 2020년 7월 16일 (목) 오후 8:05, Kees Meijs | Nefos <kees@nefos.nl>님이 작성:
Hi Seunghwan,
It might be your problem isn't BIRD but packet filter related.
Please check the BFD packets are allowed in iptables c.q. netfilter using the correct ports and/or addresses.
A possible reason why it starts working after a manual protocol restart is a ESTABLISHED, RELATED rule.
References:
- https://tools.ietf.org/html/rfc5881 (Encapsulation, IANA Considerations) - https://tools.ietf.org/html/rfc5883 (IANA Considerations)
K.
On 16-07-2020 11:00, seunghwan hwang wrote:
Hello. BFD is Not working normally. My configuration is shown below.
OS: Ubuntu 18.04 Kernel: 4.15.0-54-generic BIRD ver: 1.6.8 ================================== protocol bfd { multihop { min rx interval 300 ms; min tx interval 300 ms; multiplier 3; }; }
protocol bgp as1 { import all; export all;
local ~ as ~; neighbor ~ as ~; enable route refresh off; hold time 90; bfd on; }
protocol bgp as2 { import all; export all;
local ~ as ~; neighbor ~ as ~; enable route refresh off; hold time 90; bfd on; } ==================================
After system reboot(# shutdown -r now), BGP neighbor is established, But BFD sessions are stuck in 'INIT' status. And BIRD does not send BFD packets. BFD sessions have recovered after restart protocol bfd1(# birdc restart bfd1).
Is it a normal situation? I think BFD has to start the mechanism after BGP neighbor is UP. Is there any missing part of my configurations? Please check it.
Regards