I am using a VoIP service called webcall.ca that uses a Nortel 1001M ATA. I have been trying for weeks to get my Asterisk Server to act as a direct SIP client without having to go through the ATA.
I have tried behind my nat with nat=yes and exterip= .xxx.xxx/255.255.255.0 configure, I also tried in the DMZ and in front of my Router. There must be some little thing I am missing. My provider has told me that there is nothing they are doing on their end to prevent it from working but they of course do not support it. I know it will work because I can make a soft and hard sip phone work directly. I have my password, sip domain, and sip proxy information which is all that is needed for my service.
The only info I have been able to find so far is here.
voip-info.org/tiki-index.php … +Broadband