FAQ/How can I capture packets on a computer

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For debugging purposes, it is sometimes needed to capture network packets on a computer, for example if you have a PBX/SIP Server running on a computer on which you have access to. Such a trace can be very usefull for debugging complex SIP calls in which several phones are involved, and separate traces for each phone are harder to manage.


  • Install Wireshark (http://www.wireshark.org/download.html)
  • Start Wireshark
  • Start capturing: click the Capture menu, choose Options, press 'Start' for the appropriate interface
  • After the test is over, stop capturing by clicking Capture -> Stop
  • Save the capture by clicking File -> Save


Install tcpdump and run it using command:

tcpdump -s 0 -i any -w test.pcap 

Optional: to only capture packets from and to a particular IP address (the phone's IP address), the command would be:

tcpdump -s 0 -w test.pcap host <IP>

(replace <IP> with your IP address)

Please refer to the Wireshark wiki for further information.

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