Using sngrep tracing tool

sngrep is a tool for capturing and displaying SIP traffic. Think of sngrep as a SIP-oriented tshark/tcpdump. sngrep supports the following features:

Use a matching expression to capture data. For example, capture calls with number: 8587542200, or User-Agent: X-Lite. SIP headers and SDP supported.
Filter by calls or all type of traffic.
Stream PCAP via HEP to a capture server such as RSM.
Limit the number of SIP dialogs in your PCAP.
Combine SIP filter with standard tshark/tcpdump BPF filters (host x.x.x.x and udp, port 5060, etc).