I have a question regarding the below ACK response Kamilaio receives from a carrier.Can someone please help me understand why the "*Route: sip:callmanager@192.168.160.43:5060> *sent from Kamailio is missing a "<" as shown in the captures below? Our Internal proxy is treating that as a malformed header and dropping the packet. *ACK from CARRIER* U 2012/08/01 18:32:52.219852 4.55.18.227:5060 <http://4.55.18.227:5060> -> 192.168.160.47:5060 <http://192.168.160.47:5060> *ACK sip:callmanager@192.168.160.43:5060 SIP/2.0.* Via: SIP/2.0/UDP 4.55.18.227:5060;branch=z9hG4bK04B0eef33040e9b8e70. From: sip:+14088442721@4.55.18.227:5060;tag=gK043001e3. To: sip:+19728931740@192.168.160.47:5060;tag=b307370c678f3b44. Call-ID: 295226_50030734(a)4.55.18.227 <mailto:295226_50030734@4.55.18.227>. CSeq: 18079 ACK. Max-Forwards: 70. Route: <sip:192.168.160.47:5060;lr=on>. *Route: <sip:2c6c6d1ab58c623912f6b8a6ee526982@192.168.160.44:5060>.* Content-Length: 0. . *ACK FORWARDED TO SIP PROXY* U 2012/08/01 18:32:52.220612 192.168.160.47:5060 <http://192.168.160.47:5060> -> 192.168.160.44:5060 <http://192.168.160.44:5060> *ACK sip:2c6c6d1ab58c623912f6b8a6ee526982@192.168.160.44:5060 SIP/2.0.* Via: SIP/2.0/UDP 192.168.160.47;branch=z9hG4bKcydzigwkX. Via: SIP/2.0/UDP 4.55.18.227:5060;branch=z9hG4bK04B0eef33040e9b8e70. From: sip:+14088442721@4.55.18.227:5060;tag=gK043001e3. To: sip:+19728931740@192.168.160.47:5060;tag=b307370c678f3b44. Call-ID: 295226_50030734(a)4.55.18.227 <mailto:295226_50030734@4.55.18.227>. CSeq: 18079 ACK. Max-Forwards: 69. Content-Length: 0. *Route: sip:callmanager@192.168.160.43:5060>.* I have attached the config file for you reference. Kamailio version is 3.2.3