<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div><div>Hello,</div><div><br></div><div>We're using BIRD 1.6.4 as Route Server.</div><div><br></div><div>Recently we have decided to establish an internal BGP session between both RS over IPv6</div><div><br></div><div>But when we added our config in BIRD then it has crashed immediately with the following error:</div><div>[35878512.553496] bird6[2545]: segfault at 0 ip 000055f60242c331 sp 00007ffd43689460 error 4 in bird6[55f60240a000+86000]</div><div><br></div><div>At same time we have several working iBGP session between RS <> Routers ( not RS ) from a long time and everything works fine with them.</div><div><br></div><div>Here is the example config that crashed the system. Note: The original ASN has been replaced with 1234 in the example.</div><div><br></div><div>table T1234</div><div><br></div><div>protocol pipe P1234 from iBGP_PIPES {</div><div> peer table T1234;</div><div> export all;</div><div>}</div><div><br></div><div>protocol bgp R100 {</div><div> description "iBGP_RS1";</div><div> source address 2001:67c:29f0::A:1:234:200;</div><div> neighbor 2001:67c:29f0::A:1:234:100 as 1234;</div><div> local as myas;</div><div> prefer older on;</div><div> missing lladdr ignore;</div><div> import none;</div><div> export none;</div><div> passive off;</div><div> table T1234;</div><div> add paths on;</div><div> direct;</div><div>}</div><div><br></div><div>Another more strange:</div><div><br></div><div>Initially before the crash we have added the following config below and RS was stable but session was not able to establish. </div><div>We have made a capture of the traffic during the attempt of session establishment and seems TCP handshake works but then not procced futher.</div><div><br></div><div>Here is the config:</div><div><br data-mce-bogus="1"></div><div>template bgp iBGP {</div><div> local as myas;</div><div> import all;</div><div> export all;</div><div> import limit 21000;</div><div> passive on;</div><div> prefer older on;</div><div> missing lladdr ignore;</div><div>}</div><div><br></div><div>protocol bgp R1234x100 from iBGP {</div><div> description "iBGP_RS1";</div><div> neighbor 2001:67c:29f0::A:1:234:100 as 1234;</div><div> import all;</div><div> export all;</div><div> passive off;</div><div> table T1234;</div><div># add paths on;</div><div> direct;</div><div> import limit 4000000;</div><div>}</div><div><br></div><div>Here is the logs from both side:</div><div>Jul 7 11:52:09 rs1 bird6: R1234x4: Connecting to 2001:67c:29f0:0:a:1:234:4 from local address 2001:67c:29f0:0:a:1:234:100</div><div>2021-07-07 11:53:56 <TRACE> R1234x100: Connecting to 2001:67c:29f0:0:a:1:1234:100 from local address 2001:67c:29f0:0:a:1:234:4</div><div><br></div><div>Upper logs messages are repeating several times but iBGP was not establish.No any other logs persist in the logs message regarding this session establishment attempt.</div><div><br></div><div><div>Could someone BIRD developer to suggest some solution for fixing this issue? </div><div>We highly appreciate any kind of support.</div><div><br data-mce-bogus="1"></div><div>I had doubt that "add paths on" command would leading to this crashes but I commented it and after reloading the system crashed again.<br data-mce-bogus="1"></div><div><div>At same time this setup iBGP between the same RS over IPv4 works fine.</div></div></div><div><br></div><div>Thanks in advance!</div></div><div><br></div><div>Best~</div><div><br data-mce-bogus="1"></div><div data-marker="__SIG_PRE__"><div><div style="font-family:'tahoma' , sans-serif;color:#008081;font-size:14px">
<h2 style="font-size:14px;margin:0px;line-height:18px">Javor Kliachev</h2>
<h4 style="color:rgb( 136 , 205 , 211 );font-weight:100;margin:0px">Senior Engineer IP Services</h4>
<span class="info_type">office:</span><span class="info">+359 2 974 33 11</span><br>
<span class="info_type">mobile:</span><span class="info">+359 885 98 84 95 </span><br>
</div>
<a href="http://www.neterra.net" style="font-size:14px;font-family:'verdana';color:#008081;text-decoration:none !important" target="_blank" rel="nofollow noopener noreferrer">www.neterra.net</a>
<a href="https://bg.linkedin.com/pub/javor-kliachev/11/b46/843" style="text-decoration:none" target="_blank" rel="nofollow noopener noreferrer">
<img src="http://old.neterra.net/public/signatures/LinkedIn-icon-mini.png" class="img"> </a>
<br></div></div></div></body></html>