Re: local and remote users on same domain

6 msg	Mail gateway will not forward mail for multiple...
2 msg	postfix mangles MESSAGE-ID when passing to clamd
8 msg	Problems with either canonical_maps or alias_maps
16 msg	catchall alias for wildcard subdomains?
12 msg	Will/is there a way to prevent multiple attacks...
2 msg	Expression Assistance
2 msg	per user attachment filtering using header_checks
3 msg	Can I use reject_unlisted_sender for domain names
6 msg	sending email by Relay through ISP smtp
2 msg	duplicated messages with aliases.
4 msg	On-line RFCs in HTML without spam?

local and remote users on same domain
\ Albert (13 Jul 2007)
. \ Stuart Murray-Smith (13 Jul 2007)

11 msg	Large messages being dropped, but not by messag...
2 msg	.forward files question
1 msg	How to drop mail to a domain...
8 msg	mailbox_transport_maps as mysql table: some var...
1 msg	RE: Ruleset for incoming e-mail addresses
5 msg	custom queues
3 msg	Auto reply when winmail.dat file found
3 msg	relay_recipient_maps not working

Subject:	Re: local and remote users on same domain
Group:	Postfix-users
From:	Stuart Murray-Smith
Date:	13 Jul 2007

> The company I work for has several branches located all over the
> world. All the users receive email on the same domain (mycompany.com).
> Every user connects directly to the primary server (mail.mycompany.com
> & smtp.mycompany.com) to send/receive email. This server is located in
> the UK on a tier 1 link. The branch where I work (in South Africa)
> however is sitting on a traffic shaped 384k ADSL line with a very slow
> international link and dynamic IP. Traffic on this DSL line is also
> billed in the region of $10 per GB so it becomes quite expensive.
>
> To speed up the sending of email we have installed a Postfix server on
> our LAN through which everyone sends email. This server then relays
> the email to the ISP mail server who takes care of delivery as it is
> not accessible from the Internet.
>
> Because we have staff who travels a bit we have the name server on our
> LAN configured to point smtp.mycompany.com to the Postfix server so
> they are still able to send email when they are outside of our LAN.
>
> Most of the email in the branch is destined for people at our branch
> with some email destined for people at other branches. This comes down
> to me sending an 3MB email to 5 people at my branch and some people at
> other branches, we are wasting traffic usage as that 3MB email is
> going out once and coming in 5 times consuming 18MB of traffic instead
> of 3MB.
>
> I was thinking that we load Courier-imap on the Postfix server as well
> and have email destined to people working at our branch delivered
> locally with the rest of the email going to the primary mail server.
> For example, email for john, sarah and
> sipho should be delivered locally with email for
> pete and michelle should go to the primary
> mail server. Users shouldn't need to change the email address they
> send email to - so I shouldn't need to send email destined for
> john to john to get it delivered
> locally. Is this possible? If it is where can I read more on such a
> configuration?
>
> The next part of this would be that all email destined for people at
> my branch from people outside of my branch would go to the primary
> mail server. Here I would install fetchmail to download the email from
> the primary mail server and deliver it locally.
>
> This is where it becomes interesting. The users who travel all have
> VPN access into our LAN and 95% of the time this is fine. From
> anywhere outside of South Africa this is quite slow but it remains
> usable although I wouldn't want those users connecting to the VPN just
> to download email. Therefore I would like email destined for users who
> travel frequently or need to download email whilst on the move to end
> up at their mailbox on the primary server as well. To take the
> previous example, email for john, sarah
> and sipho should be delivered locally with email for
> john and sipho going through to the
> primary mail server as well and mail for pete and
> michelle should go only to the primary mail server. I
> guess what makes this difficult is that I wouldn't want the email that
> gets delivered locally and at the primary mail server get downloaded
> from the primary mail server again. Would this be possible?

Greetings Albert

I've got a similar scenario happening here in JHB :-)

Firstly read:

http://www.postfix.org/STANDARD_CONFIGURATION_README.html#some_local

and then consider Fetchmail to retrieve any email from the remote
server that was 'cached' there while the client was away. I have
empowered the user to toggle this functionality on and off in Webmin,
as well as set up vacation messages.

HTH

Stu@

--
Then you will know the truth, and the truth will set you free.