Here is a tip to allow easy SIP call tracing directly from Linux without needing to use TShark, or tcpdump to create and export pcap files. Install wireshark with apt-get install wireshark. It is a big install, but causes no problems to the PBX. Download and install xlaunch onto your own PC. XLaunch is an excellent open source X-Window server for Windows. You get it from Sourceforge. Run xlaunch. You will get a wizard. Choose multiple Windows, then next. Choose start a program, then next. In the start program field, type wireshark. Tick using Putty (plink.exe). Enter the IP address of the PBX computer and your login and password. Click next and next again. At this point you can save the configuration to a file which you can later double click on to automate the entire process. It is optional. When finished click Finish. At this point you should see Wireshark start on your PC as if it was running locally. Now you can do your captures and run all the cool analysis tools built into Wireshark directly on your PC. Hope this is helpful to others. Linux rocks!