What I'd like to do: have services like ntp and sendmail run after the dial up or ethernet connection is established, and stop them just before the connection goes down.

I'm using an old Dell Latitude D-505 laptop with Suse 10.2 and would like to automate the start up for some network services on a dial up or ethernet connection. I'm a truck driver, so the laptop and I are always moving around. All the connections, hardware, etc. work fine. Ntp and sendmail work okay when started manually after a net connection is up. I'd just like to automate this stuff, but can't figure out where to put the commands to do so.

I have tried Google, and tldp.org, and can't find anything on this. I'm not sure if I can add the commands to the proper if-up and if-dn scripts or if they need to be run separately. Any help is appreciated.