dear sir/madam,

we are trying to make sendmail servers to work as primary and domain servers. i will explain the current situation.

we are having mailserver sendmail(rh9), this mail server should be running without any interrupt for responding to the client. For this we made a setup with two systems(system1 & system2) having sendmail and heartbeat services configured, at a particular time in system1 sendmail and heartbeat will running and in system2 heartbeat alone will be running.
so if anything happens to the system1 (either heartbeat problem or communication problem), system2 is taking up the sendmail service using the heartbeat.(this was the things going on now for us).

"but what we need is if any thing problem comes to the sendmail service itself in system1, system2 should take over the sendmail service on its own using heartbeat."

thank in advance.

I've read about the Mon package through linux-ha.org. It sounds like what you're looking for.

Check it out