Cant PING remote computer over dial up

Hi

I wrote an application that does a data sync routing between 2 databases
over a network.  While the one pc is busy I ping it from the other to see if
it is still connected.  This works fine on my LAN but when dialing from
computer to remote using dialup I can't ping the remote computer.  This has
apparently got something to do with security.

Has anyone got any ideas of what is best way of checking to see if remote pc
is still connected and vice versa.

Thank You