In this lab, we will use a protocol analyzer to capture a complete SIP call. We will analyze the headers and the message flow. You can create this environment with a PC and two UACs. The UACs can be Softphones, ATAs, or even IP phones.
Note
Adapt this lab to your needs.
Start capturing packets using
ngrep. If it is not installed, install it using:apt-get install ngrep
To capture the packets use:
ngrep –p –q –W byline port 5060 >test.txt
Configure the UACs (Softphones, IP phones, or ATAs).
Configure the first UAC with the following configuration:
sip proxy 10.1.x.y – IP of your proxy
user: 1000
password: 1000
Configure the second UAC to the following configuration:
sip proxy 10.1.x.y – IP of your proxy
user: 1001
password 1001
After configuring the devices, you will need to register the IP Phone. Not all devices do auto registering.
Check if the phone is registered using:
openserctl ul show
At...