Mail to nonexistent User: Forward to another host?

[[email protected]]

For one of my domains, I use:

domain.com mx 10 primary.domain.com
domain.com mx 20 secondary.domain.com

If primary.domain.com goes down, then secondary.domain.com will receive email, but I do I forward it back when primary.domain.com is back online?

 

[freaky@]

Perhaps you should read up on how SMTP works...

Servers that are set up as Backup MX (ie your MX 20 record) should _NEVER_ be made final destination for the domain. Usually one needs to set it up as a relay server for domain X (I'm not aware of plesk supporting this (from the GUI), I had a post on it, if you search my nick you should be able to find it).

Once the server comes back up (the MX 10) the backup mx (MX 20) should forward it to the primary MX (MX 10). This might be delayed, as the backup MX will not be polling every second if the primary gets up.

 

[freaky@]

BTW depending on the setup, the primary MX can request the mail from the secondary MX once it comes up using ETRN (but I doubt plesk supports configuring this).

 

[[email protected]]

I agree with you, but...

My other mail servers are Kerio Mail Servers and this is one of the functionalities... Very useful and I wish I could replicate this on my Plesk...

The only option available on Plesk is to forward nonexistent users to another email address.

 

[freaky@]

? Not sure I get the question, or you don't get the answer

Use plesk as the final destination (ie the server with the pop accounts and such), use the kerio server(s) as backup mx. The kerio servers then don't need to know anything about the users for the domain, they will simply hold the mail in the queue until the primary server comes back up and then send it there. Plesk then takes care of whether or not users exist.