An Example Of Trouble With Wireshark

             The example that I am using is going to be on VoIP the first example is of a phone that’s not working every time a number is dialed, the phone idles, and no ringing is heard in the earpiece. Wireshark is used here to look at the traffic between the phone and the PBX. Launch Wireshark as root, and select the capture options to bring up the capture options. With the capture loaded select statistics VoIP calls. Wireshark analyzes the capture for any VoIP related packets and provides a summary on the screen. Click on the call and click on the Graph and scroll through the different types of options. The dialog shows the SIP messages sent by the phone. The INVITE message, which is the first step in setting up a call, IP phone is asking the PBX to place a call to a SIP address which is an echo service provider Free World Dialup for testing SIP calls. The response to this is a request for authentication, which is acknowledged. One of SIP’s jobs is to set up the RTP steam between two endpoints. It does this through the (SDP) Session Description Protocols, which carries the information about codecs, IP addresses and port number that is necessary for VoIP to work.