7800DXL and UDP port forwarding

[BobT2022]

Hi all,

I'm not new to the 7800DXL and am trying to set-up port forwarding for three UDP ports to a VOIP adapter (Grandstream HT801) for BT DigitalVoice over my new Vodafone FTTP connection.

However, no matter what I try the thing doesn't seem to want to register the VOIP account, and I've triple checked the credentials are correct and have followed the guidance on the Vodafone community portal, but I'm *convinced* the 7800DXL is still blocking the UDP ports I've set on the VOIP adapter (as required for STUN [UDP port 3478] / SIP [UDP port 5065] / RTP [UDP port 10000]).

The Grandstream HT801 has been proven to work well with Vodafone / BT DigitalVoice, so no concerns there.

The thing is I can't reliably check if those ports are open as most on-line port testers either won't work against UDP (as the nature of UDP connections differ from TCP from what I gather) and the only one that allows any hope of testing UDP ports is ipfingerprints.com using advanced settings.

I've successfully configured the VOIP adapter using a fixed IP (192.168.0.107) in the 7800DXL via Configuration --> LAN --> Static IP Lease List using the MAC address of the VOIP adapter and a fixed IP that's above the DHCP range (same as I've done with other devices where I've fixed the IP), and the VOIP adapter successfully shows the fixed IP allocation obtained the 7800DXL. As far as I can see I've also opened all three ports correctly via Configuration --> NAT --> Virtual Servers, and have configured the VOIP adapter per the guidance on the Vodafone community portal (I've tried at least several different permutations).

I've confirmed VOIP works using my Vodafone router directly (Vox 3.0) so all good there, but for the life of me can't confirm whether the UDP ports are actually open.

Using Wireshark also to sniff my local network to spot any traffic in/out of the VOIP adapter doesn't show **any** UDP activity on the ports mentioned above, thus confirming my suspicion that the 7800DXL is doing something weird.

I've ALG / SIP disabled in the 7800DXL per the guidance, and am using STUN server for NAT traversal which is showing Full Cone NAT (STUN) on the VOIP adapter so connectivity is proven.

Any ideas please as to how to confirm whether the UDP ports are indeed open on my 7800DXL as it's been driving me barmy for a few days now??

I just want to rule out any router configuration errors on my part before I ask for help in the Vodafone community portal, as others report their VOIP just working when following the same advice - ports opened of course.

Thanks in advance.

[BobT2022]

Never mind, seems to have magically worked overnight!

VOIP service registered and I can make and receive calls.

Bizarre - nothing has changed, despite the 7800DXL and VOIP adapters having been rebooted numerous times previously.