How to capture VoIP Traffic with Wireshark

Do you have a VoIP solution? If so, we may have asked you to capture your traffic data so that we can analyze it. Some vendors encrypt their traffic, making it difficult to record the actual audio. By capturing this data with Wireshark, and sending us the results, Versadial is able to review and clarify whether we can properly record.  

Note: If this is not something you’re familiar with please let us know. Or, send this to someone within your company that handles typical IT work.

Step 1

The first thing we’ll need to do is get the VoIP traffic mirrored to the computer you’d like to use for testing. This is commonly referred to as port mirroring via a SPAN or MIRROR port on your network switch. 

If you do not have a network switch capable of port mirroring, we suggest this one:

Netgear GS105E or GS105Ev2 – it’s the “E” that counts.

https://www.bestbuy.com/site/netgear-5-port-10-100-1000-mbps-gigabit-smart-managed-plus-switch-gray/7118008.p?skuId=7118008&ref=212&loc=1&gclid=EAIaIQobChMI7eWmovKQ3QIVBMpkCh3NsQZeEAQYBCABEgLYSfD_BwE&gclsrc=aw.ds

 Once you have the switch or utilizing your current switch, configure the phone port you want to test, to SPAN/MIRROR to the port of the computer you are working on. What you are doing is taking all the traffic from the VoIP phone we want to test, and copying all the traffic directing to the computer. 

Step 2

Capturing and testing the traffic. 

Software that we highly recommend you use to capture the network traffic data is Wireshark.

Wireshark is available for free here:

https://www.wireshark.org/download.html

After downloading Wireshark, please install it on the computer that you mirrored your VoIP traffic to in Step 1. 

Step 3

Once everything is properly configured, perform the following within Wireshark:

1. Start a capture.
2. Start a test call (we highly recommend you can an outside number)
3. Stop the test call.
4. Stop the capture.
5. Analyze the data.

Note: For Step 3 part 5, you can send us the test results to support@versadial.com and we can analyze the traffic for you.