iRule to ping host

Thanks Steve. I can see where those would be helpful, however the HTTP tools look like they would cost us, as the free version limits the number of sites. Using "ping" would be free :) If there is an iRule that will accomplish responding with the host IP from the client workstation when it pings the site being load balanced. Our Sharepoint admin says he was initially seeing pings of the host IP addresses in the pool, rather than the virtual IP address of the pool for the Sharepoint site, when he would ping from a client. I've not changed a setting, so is there some setting on the load-balance, via i-Rule or otherwise that would make this work?