Cannot register more than one VoIP phone

[Adamizme]

I am doing some testing on a freeSwitch based PBX that I have setup with a public IP on a separate ISP. I have 4 phones that I'm attempting to test with from my office - 2 snom and 2 fanvil phones. Whichever phone of each model registers first registers fine and works great. The second phone to attempt to register does not ever receive a response from the PBX.

This issue was happening on 16.1, so I upgraded to 16.7 and it's still happening.

Static ports are enabled in outbound NAT. None of the phones would register at all without static ports.

Enabling and disabling reflection doesn't seem to make any difference.

Firewall optimization is set to conservative.

Any other ideas of what to try?

[bartjsmit]

VoIP is notoriously sensitive to NAT. Any mileage in setting up a VPN to the pbx site?

Bart...

[Adamizme]

The PBX has a public IP assigned to it, so VPN isn't really an option and shouldn't be necessary. Multiple phones work fine with basic routers, just not opnsense.

I have roughly a couple dozen production opnsense routers, so this could be pretty problematic. If you search the internet for "pfsense multiple sip phones", it's obviously a known issue. Is there an equivalent to siproxd for opnsense? That's the only potential fix that I've read that I haven't tried, unless someone else has any other suggestions....

Thank you in advance!

[ThuTex]

try using a stun server?
in my case (though i currently only have 1 registered voip device) it always increased the stability of the connection.
you also might try to change port 5060 for 1 of the connections to something else and use port forwarding to have it end up where you want.