Hi,

I have 26 Linksys IP Phones behind NAT on a 2820. There is always one phone that will absolutely not register with my SIP server.

The original "REGISTER" gets out and reaches my server but the "unauthorized" challenge response never gets back to this phone. I can plug the phone into a different ADSL line and it will immediately come online, put it back onto the Draytek and it will refuse to register.

If I have less <= 25 phones then there is no problem.

Does this sound like (yet another) firmware issue?? I can't see it being anything else. Anybody know of any settings tweaks that might alleviate this problem?

Do you have enough IP addresses setup within the pool count for your DHCP server also have you tried setting up a static IP address on the 26th phone just to prove it is an issue with the DHCP?

cheers,