CentOS 5.7 Failover?

[faith88]

Hello,

I have some problems and i want to find the best answear.

I have one server that is running CentOS5.7
I have services like named,mail,httpd,samba,ftp and many ....
I have 2 Internet Providers one is ppoe and one is fiber(static ip on both)

I am trying to have a failover mechanism on my server.
I searched on the web and i found how to failover my 2 ISP and it is working.

But the problem is with my mail. I am running exim with tpop3d with mysql support for both.
What is the correct way to have a failover for my mail.
I don`t want to have a backup mx. I want when the internet is down on my first ISP the mail will work on my second ISP.

I have another server that i can run e-mail services if this is relevant.

I really want to know what is the corect method for this. And yes of course i want to failover the httpd but for that i found many links but my problem is my e-mail server.

Thanks.