<html dir="ltr"><head></head><body style="text-align:left; direction:ltr;"><div>Hi Colin,</div><div><br></div><div>I guess a detailed examination of the IPtables that UFW has set up might yield some clues. But you've no doubt done that already!</div><div><br></div><div>Regards,</div><div>Tony.</div><div><br></div><div>On Wed, 2019-03-13 at 22:10 +0000, Colin Law wrote:</div><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><pre>I am setting up ufw on a server and have a symptom I don't understand.</pre><pre>I am running mosquitto with TLS on port 8883 on the server so in ufw I</pre><pre>have opened that port</pre><pre>sudo ufw allow 8883</pre><pre>and can then access port 8883 from another machine, as expected. I</pre><pre>cannot access it if I do not open that port, again as expected.</pre><pre><br></pre><pre>However I also access mosquitto locally on the server using</pre><pre>localhost:8883 and the feature I do not understand is that if ufw is</pre><pre>enabled then I cannot access it via localhost whether the port is</pre><pre>opened or not. If I *disable* ufw then I *can* access mosquitto via</pre><pre>localhost.</pre><pre><br></pre><pre>ufw status shows</pre><pre>$ sudo ufw status verbose</pre><pre>Status: active</pre><pre>Logging: on (low)</pre><pre>Default: deny (incoming), allow (outgoing), deny (routed)</pre><pre>New profiles: skip</pre><pre>To Action From</pre><pre>-- ------ ----</pre><pre>22 ALLOW IN Anywhere</pre><pre>80 ALLOW IN Anywhere</pre><pre>443 ALLOW IN Anywhere</pre><pre>8883 ALLOW IN Anywhere</pre><pre>22 (v6) ALLOW IN Anywhere (v6)</pre><pre>80 (v6) ALLOW IN Anywhere (v6)</pre><pre>443 (v6) ALLOW IN Anywhere (v6)</pre><pre>8883 (v6) ALLOW IN Anywhere (v6)</pre><pre><br></pre><pre>Can anyone explain what is going on?</pre><pre><br></pre><pre>Colin</pre><pre><br></pre></blockquote><div><span><pre>-- <br></pre><div><font size="2"><font color="#3366ff"><b>Tony Arnold</b> MBCS, CITP | Senior IT Security Analyst | Directorate of IT Services | Desk 51, Office 2, Kilburn Building | The University of Manchester | Manchester M13 9PL | </font><font color="#ff0000">T:</font><font color="#3366ff"> +44 161 275 6093 | </font><font color="#ff0000">M:</font><font color="#3366ff"> +44 773 330 0039</font></font></div><div><br></div></span></div></body></html>