<div dir="ltr"><div>Hi Matus,</div><div><br></div><div>Yes. This causes serious problems.<br></div><div><br></div><div>The problem is that these perfectly valid configuration lines in /etc/named.conf file (provided that 192.168.10.100 is the IPv4 address of your DNS server, it doesn't matter if it is a primary or secondary) will cause you a lot of trouble.
</div><div><br></div><div>
<span class="gmail-im">query-source address 192.168.10.100;<br>
notify-source 192.168.10.100 port 53;<br>
transfer-source 192.168.10.100 port 53;</span></div><div><span class="gmail-im"></span><br></div><div><span class="gmail-im"></span></div><div><span class="gmail-im"></span></div><div><span class="gmail-im">These configuration lines will cause you problems as described
in my post (
BIND ignores "packets received correctly" ) from January 2020.</span></div><div><span class="gmail-im"><br></span></div><div><span class="gmail-im">It seems that this is a know issue since
BIND 9.16.1
version: UDP network ports used for listening can no longer simultaneously be used for sending traffic.<br></span></div><div><span class="gmail-im"><br></span></div><div><span class="gmail-im">Prior to this BIND version these very same configuration lines worked fine.<br></span></div><div><span class="gmail-im"><br></span></div><div><span class="gmail-im">As I said, I hope this warning
helps someone else to avoid loosing a lot of time trying to find out what is happening to their DNS servers running BIND 9.16.1+
</span></div><div><span class="gmail-im"><br></span></div><div><span class="gmail-im"></span></div><div><span class="gmail-im">Regards,<br></span></div></div><div id="DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br> <table style="border-top:1px solid #d3d4de">
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<a href="#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2" width="1" height="1"></a></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">El lun, 25 ene 2021 a las 11:13, Matus UHLAR - fantomas (<<a href="mailto:uhlar@fantomas.sk">uhlar@fantomas.sk</a>>) escribió:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On 23.01.21 12:44, Bernardo wrote:<br>
>Finally I've found the solution.<br>
>The problem seems to be caused by a known issue since BIND version 9.16.1<br>
><br>
>Commenting out these lines in /etc/named.conf solves the issue:<br>
><br>
>query-source address 192.168.10.100;<br>
>notify-source 192.168.10.100 port 53;<br>
>transfer-source 192.168.10.100 port 53;<br>
<br>
this should not cause a problem and may cause troubles when 192.168.10.100<br>
is not the primary address.<br>
<br>
the "port 53" is usually useless (unless you have stateless firewall) and<br>
may be what caused your problem.<br>
<br>
-- <br>
Matus UHLAR - fantomas, <a href="mailto:uhlar@fantomas.sk" target="_blank">uhlar@fantomas.sk</a> ; <a href="http://www.fantomas.sk/" rel="noreferrer" target="_blank">http://www.fantomas.sk/</a><br>
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</blockquote></div><br clear="all"><br>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div><span style="font-size:12.8px">Bernardo</span><br></div></div></div></div>