<div dir="ltr">Hey,<div>thank you! I think I am having the same problem they had here: </div><div><a href="https://bird.network.cz/pipermail/bird-users/2010-September/001620.html">https://bird.network.cz/pipermail/bird-users/2010-September/001620.html</a> </div><div><br></div><div>But I didn't understand how they solved.</div><div><br></div><div>Regards,</div><div>Fabiano <br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Il giorno lun 6 apr 2020 alle ore 17:16 Cybertinus <<a href="mailto:bird@cybertinus.nl">bird@cybertinus.nl</a>> ha scritto:<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 style="font-size:10pt;font-family:Verdana,Geneva,sans-serif">
<p>Hello Fabiano,</p>
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<p>BGP Communities are basically tags you add to a prefix that is received from, or send to, a peer. And in Bird you can do whatever you want with these communities. A community by itself has no meaning and has no influence on the routing decision whatsoever. It is the meaning you add to it in your configuration what makes them work.</p>
<p>More information about communities: <a href="https://en.wikipedia.org/wiki/Border_Gateway_Protocol#Communities" target="_blank">https://en.wikipedia.org/wiki/Border_Gateway_Protocol#Communities</a></p>
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<div style="margin:0px;padding:0px;font-family:monospace">Kind regards,<br>Cybertinus</div>
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<p id="gmail-m_-510029749969709659reply-intro">On 2020-04-06 17:03, Fabiano D'Agostino wrote:</p>
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<div dir="ltr">and how these kind of checks are handled?
<div><span style="color:rgb(22,22,22);font-family:"PT Sans",HelveticaNeue,"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px">if (myas,peeras) ~ bgp_community</span> <span style="color:rgb(0,0,255)">what is bgp_community?</span></div>
<div><span style="color:rgb(0,0,255)"> </span></div>
<div><span style="color:rgb(0,0,0)"><span style="background-color:rgb(243,243,243)">Thanks, </span></span></div>
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<div dir="ltr">Il giorno lun 6 apr 2020 alle ore 15:32 Fabiano D'Agostino <<a href="mailto:fabiano.dagostino96@gmail.com" rel="noreferrer" target="_blank">fabiano.dagostino96@gmail.com</a>> ha scritto:</div>
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<div dir="ltr">Thank you, but "if the route does not come from BGP then false"
<div>here I have:</div>
<div>protocol pipe a {<br> table master;<br> mode transparent;<br> peer table a;<br> import all; <br> export where bgp_out(x); => <span style="color:rgb(0,0,255)">this becomes false, what does this mean?</span><br> #export all;<br>}</div>
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<div>Thanks,</div>
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<div dir="ltr">Il giorno lun 6 apr 2020 alle ore 10:50 Bernd Naumann <<a href="mailto:bena@spreadshirt.net" rel="noreferrer" target="_blank">bena@spreadshirt.net</a>> ha scritto:</div>
<blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On 05.04.20 23:08, Fabiano D'Agostino wrote:<br>> Good evening,<br>> could someone explain me the meaning of these lines?<br>> <br>> function bgp_out(int peeras)<br>> {<br>> if ! (source = RTS_BGP ) then return false;<br>> if peeras > 65535 then return true; ### communities do not support AS32<br>> if (0,peeras) ~ bgp_community then return false;<br>> if (myas,peeras) ~ bgp_community then return true;<br>> if (0, myas) ~ bgp_community then return false;<br>> return true;<br>> }<br>> <br>> Thanks,<br>> <br>> Fabiano<br>> <br><br>Morning,<br><br>I can not cover the whole section but as a start...<br><br>* if the route does not come from BGP then false (routing table source?)<br>* if the remote AS Number is greater 65535 (16 Bit) then "just" return <br>true (see AS 32 Bit Numbers, and the non-support of older <br>devices/implementations)<br>* For the next 3 I'm not 100% sure how to read but I found <br><a href="https://bird-users.network.narkive.com/3uDbo6H9/any-ix-willing-to-share-their-config" rel="noopener noreferrer" target="_blank">https://bird-users.network.narkive.com/3uDbo6H9/any-ix-willing-to-share-their-config</a><br><br>```<br>0:XXXXX - Do not announce route to peer XXXXX<br>0:MyASN - Do not announce route to all peers<br>MyASN:XXXXX - Announce route to peer XXXXX only<br>MyASN:MyASN - Announce routes to all peers. This community is<br>automatically added to all routes that are not<br>tagged with any of MyASN:XXXXX communities.<br>```<br><br>Maybe this helps a little bit.<br><br>Bernd</blockquote>
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