i think the ping thing wont work...
1- you have to send a lot of packets to someone, so this person may ping timeout
2 - Ddos'ing someone its not like that, it wont ping timeout no one, since server will only answer you the time between your connection and server connection
try

//ping $server

doesnt matter what nickname or name you put in /ping it will always returns your connection delay

by the way a /ctcp ping may be blocked by users in UnrealIRCd using the usermode +T

you have to use a lot of connections to ping timeout someone