[Serusers] Ignored registrations?

I'm having a small problem with a phone registration at a customer's site. The majority of the phones register with no problem. The ones that register correctly are Snom 200s, while the one I'm having problems with is a Cisco. The registration request I see in my ngrep log from the Cisco is: REGISTER sip:SIP000BBEF2DF4C SIP/2.0..Via: SIP/2.0/UDP 172.21.20.200:5060.. From: sip:Line1@SIP000BBEF2DF4C..To: sip:Line1@SIP000BBEF2DF4C..Call-ID: 000bbef2-df4c000c-223725a3-671cea85@172.21.20.200..CSeq: 101 REGISTER..Contact: <sip:Line1@172.21.20.200:5060>..Expires: 3600..Content-Length: 0.... While a Snom's request looks like this: REGISTER sip:172.21.30.50 SIP/2.0..Via: SIP/2.0/UDP 172.21.20.36:5060;branch=z9hG4bK-zqvjm58v73fd;rport..Max-Forwards: 70..From: "IC36" <sip:IC36@172.21.30.50>;tag=26kqteejq4..To: "IC36" <sip:IC36@172.21.30.50>..Call-ID: 3ef763ebf18c-ga88nc7dymyf@172.21.20.36..User-Agent: snom200-1.15r..CSeq: 1581 REGISTER..Route: <sip:172.21.30.50>..Contact: <sip:IC36@172.21.20.36:5060;line=1>..Expires: 600..Content-Length: 0.... There's never a response of any kind from the SER proxy to the Cisco's request. I noticed that the Cisco doesn't enlcose the From or To addresses in <>'s, while the Snom and other SIP devices at the location do, but I'm not sure that's the problem. Ideas? -- Jamin W. Collins This is the typical unix way of doing things: you string together lots of very specific tools to accomplish larger tasks. -- Vineet Kumar