zimbra as a backup mail server

[zoranb]

Hello all,
I have running zimbra 8.8 with domains for example: mydomain1.com and mydomain2.com.
A friend has his own server for his domain, sys: hisdomain.com

We would like to prepare a backup configuration for hisdomain.com, such that
when his server is down, my (zimbra) server would accept all mail for hisdomain.com
and relay it to his server once it is online again.
I belive that we need to setup his secondary MX record to point to zimbra.

The question is:
How to configure zimbra site to accept mail for hisdomain.com and act as relay server?

regards,
Zoran

[lytledd]

Take a look at the below Wiki Article,

Doug

https://wiki.zimbra.com/wiki/Managing_Domains

[zoranb]

I have followed the instructions.
The first command gives "no such domain" error.

Do I suppose to create a domain first?
If yes, does this new (external) domain need any special configuration or is it created like any other (local) domain?

In a standalone postfix (/etc/posftix/main.cf), there is a "relay_domains" configuration item which does what I need.
Is there any way to insert this configuration to postfix via zimbra commands (that is: zimbra is aware of this configuration
and is changed during upgrades)?
Is this procedure (as described in this link: https://wiki.zimbra.com/wiki/Managing_Domains)
functionally equivalent what postfix does, using "relay_domains"?

Zoran

[lytledd]

Do I suppose to create a domain first?
If yes, does this new (external) domain need any special configuration or is it created like any other (local) domain?

Yes.

You will have entries on your mail server for your friend and your friend will have domain entries on your server.

We used this option when we started trialing Zimbra. We set it up that all incoming mail hit the Zimbra server first and then did a domain forward to our old mail server.

You would set up your friend's domain in your Zimbra server, just like a normal local domain and then do a domain forward to his server. When his server would be offline, the secondary MX would point to you. Your server would receive that mail and queue it until it can be delivered.

Doug

[zoranb]

Doug,
thank you for your suggestion. After creating a domain, the forwarding works.

Just one more question regarding retention time.
If for example a friend's server is down and my server has received some mail for his domain...
How long will my server (zimbra) try to deliver the mail, before giving up?
What happens with the mail after giving up?

Zoran

[lytledd]

How long will my server (zimbra) try to deliver the mail, before giving up?

Indefinitely, as far as i Know,

Doug

[phoenix]

Indefinitely, as far as i Know,

Isn't the Postfix "maximal queue lifetime" five days? As far as I know it is but it can be changed.