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Hello Ben,</div>
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our experience shows that having logs in Wireshark doesn't necessary means that they reach the applications. (Wireshark captures packets on the interface level.)</div>
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So as a first step I would recommend to clarify that the logs from the second host indeed reaches Syslog-ng. (For UDP logs netcat usually is enough.)</div>
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Once it is clear that those logs reaches the application level, we can focus on debugging Syslog-ng.</div>
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By starting Syslog-ng with the following options, it would be much easier to examine the flow of messages:</div>
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syslog-ng -Fdevt</div>
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-F : start it in the foreground</div>
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-d : debug mode</div>
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-e : log messages to stderr</div>
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-v : increases verbository</div>
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-t : also enable trace messages</div>
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Note: With these options enabled, Syslog-ng will produce a LOT of messages. So if you can turn off other logging sources temporary, than it will be much more easier to read those logs.</div>
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At this point you should start to receive this kind of debug messages, which will indicate that Syslog-ng received the log messages from your host:</div>
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[2020-08-28T10:09:43.289660] Incoming log entry; line='hello world'<br>
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>From this point the easiest way is to start with a minimal config, and build up your final configuration step by step. Checking incoming logs in each steps.</div>
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Br,</div>
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Laci</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> syslog-ng <syslog-ng-bounces@lists.balabit.hu> on behalf of Bruns, Benjamin <Benjamin.Bruns@cypp.de><br>
<b>Sent:</b> Friday, August 28, 2020 11:53<br>
<b>To:</b> syslog-ng@lists.balabit.hu <syslog-ng@lists.balabit.hu><br>
<b>Subject:</b> [syslog-ng] syslog-ng is ignoring a network source</font>
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<p class="x_MsoNormal">Hello!</p>
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<p class="x_MsoNormal"><span lang="EN-US">I try to send syslogs from two firewalls to my syslog-ng host. The first one worked immediately, but logs of the second firewall seems to be ignored. Both syslogs come in via UDP on port 514 and I can see them in Wireshark
on my syslog-ng host, but they disappear for my second firewall in a black hole. Both have Logstash as their destination configured. Any ideas? Thanks in advance!</span></p>
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<p class="x_MsoNormal"><span lang="EN-US">Cheers, Ben</span></p>
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