Failover with DNS

[Mohammed Ghanawi]

I would like to configure a failover system using DNS, so that

if mail1.domain.com fails all mail should be routed to mail2.domain.com
if web1.domain.com fails all HTTP traffic should be routed to
web2.domain.com
is ldap1 fails the use ldap2

I usually duplicate mail1 and mail2, web1 and web2, ldap1 and ldap2.

right now I have aliases

mail -> mail1
web -> web1
ldap -> ldap1

if web1 fails for example, I just go to the dns server and point web to
web2, same for mail and ldap.

Is there a way to make this automatic with DNS ?

Thanks for the help