I have been doing some test to replace a very expensive licensed base Alcatel system with an Asterisk box. I have been real impressed the the PIAF load and got a couple of variations running, making calls and even have it connected to the Alcatel box via T1. I have tested different softphones and a couple of SIP phones, but decided to give the Aastra 6757i a spin after reading Ward Mundy's blog about it. For the most part, I like the phone, but I have a problem with it saying "No Service". When it boots it shows "Network Connected". The astriskCLI shows it connect. But about 2 seconds after the "Network Connected" message, it goes to the "No Service". I looked at the status via the phone web interface, under System Information and it shows a status of 403 for SIP status. I checked the AsteriskCLI using a sip show peers and it shows the phone connected. I thought it might be the username/password issue, but the config file has the correct and I double tested it via a softphone. Thought it might be iptables or fail2ban, so I shut those services down for testing. Still get the status 403. Anyone got an idea?