<div dir="ltr">Hello K.<div><br></div><div>Thanks for checking in this issue.</div><div>But, I can't understand.</div><div>If it was because of the iptables, it would have been a problem for BGP as well.<br></div><div>And I'm not using iptables rules, So Any packets weren't dropped.</div><div><br></div><div>* iptables status</div><div>============================================================</div><div># iptables -L<br>Chain INPUT (policy ACCEPT)<br>target prot opt source destination<br><br>Chain FORWARD (policy ACCEPT)<br>target prot opt source destination<br><br>Chain OUTPUT (policy ACCEPT)<br>target prot opt source destination<br>============================================================<br></div><div><br></div><div>* Port status<br>============================================================ </div><div># netstat -lnp | grep bird<br>tcp 0 0 <a href="http://0.0.0.0:179">0.0.0.0:179</a> 0.0.0.0:* LISTEN 44890/bird<br>udp 0 0 <a href="http://0.0.0.0:3784">0.0.0.0:3784</a> 0.0.0.0:* 44890/bird<br>udp 0 0 <a href="http://0.0.0.0:4784">0.0.0.0:4784</a> 0.0.0.0:* 44890/bird<br>unix 2 [ ACC ] STREAM LISTENING 320049 44890/bird /run/bird/bird.ctl<br>unix 2 [ ACC ] STREAM LISTENING 398938 44893/bird6 /run/bird/bird6.ctl<br></div><div>
============================================================
<br></div><div><br></div><div>* BIRD Status<br>============================================================ </div><div># birdc show bfd sessions<br>BIRD 1.6.8 ready.<br>bfd1:<br>IP address Interface State Since Interval Timeout<br>10.11.251.4 --- Init 09:37:57 2.000 6.000<br>10.11.250.4 --- Init 09:37:56 2.000 6.000<br></div><div><br></div><div># birdc show protocols<br>BIRD 1.6.8 ready.<br>name proto table state since info<br>kernel1 Kernel master up 09:37:52<br>direct1 Direct master up 09:37:52<br>device1 Device master up 09:37:52<br>static1 Static master up 09:37:52<br>bfd1 BFD master up 09:37:52<br>as1 BGP master up 09:37:56 Established<br>as2 BGP master up 09:37:57 Established<br></div><div>
============================================================
<br></div><div><br></div><div>Is it related to the increase in this value?<br></div><div><div>============================================================<br></div><div># netstat -s</div><div>...</div><div>Udp:<br> 52759 packets received<br> 0 packets to unknown port received<br> 0 packet receive errors<br> 34365164 packets sent<br> 0 receive buffer errors<br> 0 send buffer errors<br> IgnoredMulti: 3399<br>...</div><div><div>============================================================<br></div><div><br></div><div>Please check it.</div><div><br></div><div>Regards.</div><div></div></div><div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">2020년 7월 16일 (목) 오후 8:05, Kees Meijs | Nefos <<a href="mailto:kees@nefos.nl">kees@nefos.nl</a>>님이 작성:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
Hi Seunghwan,<br>
<br>
It might be your problem isn't BIRD but packet filter related.<br>
<br>
Please check the BFD packets are allowed in iptables c.q. netfilter
using the correct ports and/or addresses.<br>
<br>
A possible reason why it starts working after a manual protocol
restart is a ESTABLISHED, RELATED rule.<br>
<br>
References:<br>
<ul>
<li><a href="https://tools.ietf.org/html/rfc5881" target="_blank">https://tools.ietf.org/html/rfc5881</a> (Encapsulation, IANA
Considerations)<br>
</li>
<li><a href="https://tools.ietf.org/html/rfc5883" target="_blank">https://tools.ietf.org/html/rfc5883</a> (IANA Considerations)<br>
</li>
</ul>
<br>
K.<br>
<br>
<div>On 16-07-2020 11:00, seunghwan hwang
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hello.
<div>BFD is Not working normally.</div>
<div>My configuration is shown below.</div>
<div><br>
</div>
<div>OS: Ubuntu 18.04</div>
<div>Kernel: 4.15.0-54-generic</div>
<div>BIRD ver: 1.6.8</div>
<div>==================================</div>
<div>protocol bfd {<br>
multihop {<br>
min rx interval 300 ms;<br>
min tx interval 300 ms;<br>
multiplier 3;<br>
};<br>
}<br>
</div>
<div><br>
</div>
<div>protocol bgp as1 {<br>
import all;<br>
export all;<br>
<br>
local ~ as ~;<br>
neighbor ~ as ~; <br>
enable route refresh off;<br>
hold time 90;<br>
bfd on;<br>
}<br>
<br>
protocol bgp as2 {<br>
import all;<br>
export all;
<br>
<br>
local ~ as ~;<br>
neighbor ~ as ~; <br>
enable route refresh off;<br>
hold time 90;<br>
bfd on; <br>
}<br>
</div>
<div>================================== <br>
</div>
<div><br>
</div>
<div>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.<br>
</div>
<div>BFD sessions have recovered after restart protocol bfd1(#
birdc restart bfd1).</div>
<div><br>
</div>
<div>Is it a normal situation?</div>
<div>I think BFD has to start the mechanism after BGP neighbor
is UP.</div>
<div>Is there any missing part of my configurations?<br>
</div>
<div>Please check it.</div>
<div><br>
</div>
<div>Regards</div>
</div>
</blockquote>
<br>
</div>
</blockquote></div>