What is a SIP via header?
The Via header identifies the protocol name (SIP), protocol version (2.0), transport type (e.g. UDP or TCP), IP address of the UAC, and the protocol port (typically 5060) used for the request. This information allows the recipient of the request (a user agent server) to return SIP responses to the correct device.
What is difference between Via and contact header in SIP?
Note: The URI of the Contact header is used to route future requests. For the routing or SIP responses within the dialog, the VIA header is used instead.
What is via SIP?
Session Initiation Protocol (SIP)
The Session Initiation Protocol is a signaling protocol that enables the Voice Over Internet Protocol (VoIP) by defining the messages sent between endpoints and managing the actual elements of a call.