I realise i should probably looking to the VOIP phone support people, believe me i am on it, but after a recent firmware upgrade of an LG iPECS system what was previously working fine now works intermittently throuhg our Sophos SG UTM. Callers can't be heard when they ring through, but not on all all calls, some are fine. when testing if i consistently keep trying, voice will eventually come through in both directions.
Our system previously relied on firewall rules and NAT, we had more immediate success going down this route originally rather than the VOIP module which was tried at the time, and since it was been working the firewall settings have very much been left alone over the years.
Since the phone system's firmware was upgraded (we needed to to add more extension licenses apparently) and we've had this issue I have searched the forums and tried various things.. i think i need to rewind and start again.
I'm not getting any specific DROP in real-time firewall logs i can see to think to open things up further, even the full logs don't seem to suggest anything different to me, though I'm a one man band in an SMB an not much of an expert.
Any advice on where i should start trouble shooting from scratch?
Thank you!
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