Use tcpdump and wireshark to debug VoIP calls

By January 3, 2017Tutorials

Tips: In some cases, the system environment is more complicated, we hope to get the complete call information, then we can use tcpdump access to network data, the use of wireshark for further analysis.

1、If don’t have tcpdump, please do as follows:
yum install -y tcpdump


2、The capture command is executed and the captured information is saved in a file.
tcpdump -i any -s 65535 -w internal.pcap

Indicates that packets received by any network interface are saved to the internal.pcap file.


3、Start tcpdump capturing packets:

tcpdump voip调试


4、After the implementation of the system will stop here, this time we can make a phone call, and then use “Ctrl+c” to end.

tcpdump voip调试

Tcpdump will output some capturing packet information, so tcpdump’s mission is complete, download the pcap file and turn the wireshark.


5、Wireshark can download from,install and run wireshark, then open the internal.pcap file.

Here we can see tcpdump caught a variety of packages, the use of “Telephony” under the “VoIP Calls”, the system will automatically summarize during the call.


wireshark VoIP调试


6、Select a call, click the Flow button, wireshark will use a graphic to represent the call, click the appropriate steps, we can see the corresponding IP packet information.