I managed to find a small hole in a web application that appeared as if it wold allow me to execute commands on the local machine.  I tried a simple reverse shell but no joy.  Taking it down to a very basic level, I tried to ping but I needed to capture my ping requests on the other end.  

I executed the following:

tcpdump ip proto \\icmp -i eth0

to which it responds with:

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes

[side note]

Which interface are you using?

The following command will identify your interface:

ifconfig -a

Replace eth0 with your interface.

[/side note]

Now that you've got tcpdump setup, you can initiate your ping command injection and if it succeeds, you should see the following on the machine catching the request:

18:44:50.816725 IP victim.sevenlaeyrs.com > 10.16.10.111: ICMP echo request, id 24908, seq 1, length 64
18:44:50.816775 IP 10.16.10.111 > victim.sevenlaeyrs.com: ICMP echo reply, id 24908, seq 1, length 64
18:44:51.817506 IP victim.sevenlaeyrs.com > 10.16.10.111: ICMP echo request, id 24908, seq 2, length 64
18:44:51.817544 IP 10.16.10.111 > victim.sevenlaeyrs.com: ICMP echo reply, id 24908, seq 2, length 64