On 2011-09-03 02:40, Daniel Mare wrote:
We have Head Office and Small Office.
In Head Office, we have Mac OS X 10.6.7 Mail server (i.e. postfix). For people
in Head Office, traffic to and from the mail server is over the fast LAN - no
problems.
In Small Office, we have two employees, let's call them Snail and Shoe.
Currently Snail and Shoe use the mail server in Head Office. When Snail emails
Shoe, the message travels all the way to Head Office saturing the slow link
upstream. Shoe then downloads the email from Head Office, which then saturates
the slow link downstream.
If Snail and Shoe are on the same LAN in the small office, there shouldn't be
any reason for the message to travel all the way back to head office, so my
question is:
How do I set up a local email server in Small Office using the same email
domain?
If Snail sends an email to Shoe, it would go to a local email server in Small
Office. The local email server in Small Office would then check if Shoe is
located in Small Office, if not, it would pass the message on the Head Office,
but in this case, seeing that Shoe is in the local Small Office, the local mail
server would then keep the message in Small Office. Shoe will then download it
from Small Office's local mail server, saving the slow link from saturation.
How do I do set up the servers this way?
Install a new postfix server at the satellite location, and either give
it its own mail domain (and MX record), or set up transports to those
two users.
In case the former is unpractical, or impossible, for instance because
the second server is on an internal LAN only (think VPN), you can use
transport_maps on the main mail server to deliver mail for those two
users to the satellite office.
The satellite mail server should be configured to accept mail for its
local users, and route mail for other users back to the main server; the
simplest way to do this is to alias the valid users to a separate
mailbox domain, and relay the original domain back to the main server.
However, even the above can be achieved in half a dozen distinct ways,
and there is no single correct solution; it depends on additional
requirements, such as: will the satellite system send its own external
mail ? and: is there a centralized user database available for use by
both systems ?
More information can be found in the documentation, such as
http://www.postfix.org/STANDARD_CONFIGURATION_README.html#some_local and
http://www.postfix.org/ADDRESS_REWRITING_README.html
--
J.
