How to Blocking VoIP ( H.323) ?

[Joe Shen <joe_hznm () yahoo com sg>]

Hi,

How could it be done to block VoIP at access router?

I've thought about using ACL to block UDP port
1719,but this could be overcome by modifying protocol 
port number. 

regards

Joe 

__________________________________________________
Do You Yahoo!?
Log on to Messenger with your mobile phone!
http://sg.messenger.yahoo.com