First, ping -a will give you a hostname that an IP resolves to, if the IP is registered in DNS, or a nameservice. If not, you'll get the same address returned as a result, similar to what you get without the -a. So, it's useful if you have an IP you're looking at, and want to see what hostname belongs to the address. Say you review a log, and see an IP regularly hits your firewall. You might try -a, to see if you can determine the host. Subsequently, in a test, you might ping sweep a range of addresses, to see which are responding. You might then try to see what the ones are, that respond to the initial sweep.
Next, -t is handy if you're doing connectivity testing. For instance, if you suspect you have connection issues, or want to see if there's packet loss, etc, you might run a continuous ping, to see if you are not getting responses to all your ping packets (meaning it either dropped your outbound packets, or the return packets, somewhere.
There are other scenarios where you might use it, but that's one example.
As for stopping it, the combination of ctrl-c essentially stops the running ping process, in it's tracks. Like 'break'
Last edited by hayabusa
on Fri May 27, 2011 8:40 pm, edited 1 time in total.
~ hayabusa ~
"All men can see these tactics whereby I conquer, but what none can see is the strategy out of which victory is evolved." - Sun Tzu, 'The Art of War'
OSCE, OSCP , GPEN, C|EH