Secondary internet connection as backup

[Spencer]

Would it be possible to use a secondary connection, such as a DSL line, with static IP to use as a secondary route for zimbra?

Scenario would be if our primary internet line would go down, mail would failover to the DSL line as mail2.example.com.

Would Zimbra receive the mail properly even if the dns is different?

[ArcaneMagus]

You could try something like setting up a secondary MX record pointing to an A record that has the IP address of the second line on it and give it a way lower priority (higher number in bind) so that it will only be used if the main address is down. Make sure that it has a valid PTR record.