On TARGET host

nc -u -l 4569

On SOURCE host

nc -u TARGET.IP 4569

Type in anything, and what you write should appear on the TARGET host output.

This tests that a connection can be established on port 4569 UDP. Don't forget to test the other way round.

On TARGET host

nc -l 5060

On SOURCE host

nc -u TARGET.IP 5060

Type in anything, and it should appear on the TARGET host.

This test that data can flow between the two hosts via port 5060 TCP. Note that SIP typically uses UDP over TCP.

ping TARGET.IP

Ctrl+C to stop

Checks host is up and reachable. Note that some servers may be configured to ignore ICMP Echo requests (pings).

Also useful for determining latency. Should be under 150ms

traceroute TARGET.IP

Checks route taken to TARGET. Useful for identifying which gateways the data takes to reach the target.

Sometimes it may be necessary to analyse SIP or other network data.

Ensure ngrep is installed on the server. Also install Wireshark on your desktop.

For all traffic on the SERVER run:

tcpdump -i eth0 -s 1500 -w trafficCapture.pcap

Leave for 5 to 10 minutes, or make a test call. Then press Ctrl+C to stop capture.

For pure SIP run:

### capture all SIP packets on 5060 on all interfaces
ngrep -W byline -td any . port 5060

### capture all SIP packets containing 'username' on port 5060 on all interfaces
ngrep -W byline -tqd any username port 5060

If Wireshark is on a different computer than the server, tar -czf FILENAME.tgz FILENAME.cap to compress it.

Transfer the file via rsync or scp or another method to the Wireshark computer (you may want to take md5sum or sha1sum).

rsync -avh --progress FILENAME.tgz user@DESKTOP:~
scp FILENAME.tgz user@DESKTOP:~

Note the above rsync/scp commands may not work as expected if you are behind a NAT.