Re: [Exim] one domain, multiple POP3 hosts

Top Page
Delete this message
Reply to this message
Author: Robert Lister
Date:  
To: Rick Duvall
CC: exim-users
Subject: Re: [Exim] one domain, multiple POP3 hosts
On Mon, Nov 19, 2001 at 04:46:34PM -0800, Rick Duvall wrote:
> I remember reading something back in 1999 on this list something about
> setting up email service at an ISP with multiple POP's in the following
> configuration, with 1 domain name:
>
> MX1/POP1        MX2/POP2         MX3/POP3
> Florida                Oregon                Nevada

>
> Each POP would be a separate city, and need to have their own SMTP server
> and own POP3 server so that POP3 and SMTP traffic isn't backhauled across
> the internet to the main mailhub. What would happen is each SMTP server
> would have a usermap containing the $local_part and mailhost. All
> mailservers operate POP3 for the same domain. So if john@???
> existed at MX1, but the message arrived at MX3, then MX3 would relay the
> mail to MX1, and drop it in john's pop box.
>
> Does anybody know how to make this happen?


Sounds like a simple case of getting aliases files working
on each system such that they know which users should be accepted
locally and which users are on other hosts in your domain.

So, MX1 and MX3 would have:

fred:fred@???

In the aliases file.

This would be fairly seamless to the user as your MX records
would accept "fred@???" and exim will internally
route it to "fred@???"

For the local users (in this example on MX2), the setup
would be similar to a virtual domain (i.e. unless you want
real /etc/passwd users) the would be set up as virtual mailboxes.

There's other fancier ways of doing the same thing, like using
LDAP etc if you want a way to easily distribute the
information across all three mail hosts, as obviously all three
must agree on where the user is.

Regards,



Rob