Strange firewall behaviour with trunk not receiving 200 OK

siptrunk
pjsip
freepbx
Tags: #<Tag:0x00007f7032a41268> #<Tag:0x00007f7032a409f8> #<Tag:0x00007f7032a403e0>

(Jeroen) #1

Our firewall is showing weird behaviour lately. It started with the issue as recorded here:

https://community.freepbx.org/t/pjsip-trunk-dns-srv-unstable-only-ip-address-working/73361

It turns out that the 200 OK responses from our VOIP provider are actually blocked by the Freebpx firewall. For a long period of time it seems to go well - 200 OK responses are returning and the trunks remail online. But then after several hours (quite unknown how long) all trunks appear offline. They only come back online when we disable the firewall.

When we enable the firewall again the trunks remain online for a long period before they appear offline again.

At first we thought it was because we hadn’t whitelisted either the domain of the SRV record or the IP addresses - even though the connection is made outbound. But even adding these details the trunks remain online for a while and then suddenly appear offline again.

We have the responsive firewall enabled on SIP.

Can anyone help us what settings could block the 200 OK response and how we can log the firewall to see what connections and why are blocked by the firewall.


(Sam Shomi) #2

I would disable the firewall completely. It’s too opinionated and adds unnecessary complexity and you end up fighting with it and having stuff like this happening. This module has caused far more problems for me than it has ever solved. I ended up spending more time than I normally would just setting up firewalld from CLI without it locking me out and all kinds of other stuff.