hi-
looking at branch parameter of Via header field in INVITE and ACK.
the RFC 3261 said:
"The ACK MUST contain a single Via header field, and this MUST be equal to the top Via header field of the original request." at page 129 "17.1.1.3 Construction of the ACK Request".
my proxy server retransmit 200ok until timeout and hangup the call because never receive an ACK.
INVITE sip:243450030@192.168.0.4 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.55:5070;rport;branch=z9hG4bK5465424
To: <sip:243450030@192.168.0.4>
From: "Emanuel" <sip:243450029@192.168.0.4>;tag=856
Call-ID: 1140978178-424-EMANUEL@192.168.0.55
CSeq: 32 INVITE
Max-Forwards: 20
User-Agent: Express Talk 1.03
Contact: <sip:243450029@192.168.0.55:5070>
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, INFO, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: 281
ACK sip:243450030@192.168.0.4 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.55:5070;rport;branch=z9hG4bK5466424
To: <sip:243450030@192.168.0.4>;tag=11413226489683348
From: <sip:243450029@192.168.0.4>;tag=856
Call-ID: 1140978178-424-EMANUEL@192.168.0.55
CSeq: 32 ACK
Max-Forwards: 20
User-Agent: Express Talk 1.03
Content-Length: 0