1 Topic by Volker

  • Volker
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Topic: iRedMail as relay server between internet and MS Exchange server

==== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.4
- Linux/BSD distribution name and version: CentOS 7
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): PGSQL
- Web server (Apache or Nginx): Apache
- Manage mail accounts with iRedAdmin-Pro?
- Related log if you're reporting an issue:
====

Dear Zhang Huangbin,

once more thank you very much for your great product and outstanding support!

Since I got a customer who is in need of an AntiVirus-/AntiSpam- Solution I'm considering to recommend iRedMail for that purpose. He will not need "a whole Mailserver", since he is currently using MS  Exchange. My plan is to install iRedMail on clean CentOS 7-Server as kind of mail relay between the internet and his Exchange-Servers. It should receive E-Mail for several domains (*@domain.com; not only single mailboxes), check it for Virii and Spam, delete/keep the "bad mail" and forward the "good mail" to the exchange servers.

Can you give me any hints/tips regarding this plan? Is there any complete HowTo, regarding "CentOS 7", "iRedMail as relay" (without using the local mailboxes on the iRedMail host). I have done some searches already, but couldn't find any solution which deals with all these requirements.

Finally also my question, if iRedMail can do this job or if it needs iRedAdmin Pro in order to do so.

Your reply would be greatly appreciated. Thank you very much!


Best regards,

Volker

----

Spider Email Archiver: On-Premises, lightweight email archiving software developed by iRedMail team. Supports Amazon S3 compatible storage and custom branding.

2 Reply by Frankstar (edited by Frankstar 2016-04-24 22:26:53)

  • Frankstar
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Re: iRedMail as relay server between internet and MS Exchange server

actually you can install a "normal" iredmail.
And than adjust Postfix.

They main config is in the Transport.
You will have something like this after the install:

cat /etc/postfix/transport

mydomain.com       dovecot
myotherdomain.com     dovecot

Change it to deliver the mails not to dovecot but to your exchange server.
like

mydomain.com      smtp:[10.10.10.50]
myotherdomain.com     smtp:[10.10.10.50]

where 10.10.10.50 is the ip of you exchange server.

also make sure that "local_recipient_maps =" in postfix main.cf is set / uncomment it.
No parameter need be set - just:

local_recipient_maps =

This will force Postfix to not lookup local recipient. This way, Postfix will accept all mails address to the destination domain(s).

3 Reply by ZhangHuangbin

  • ZhangHuangbin
  • ZhangHuangbin
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  • Registered: 2009-05-06
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Re: iRedMail as relay server between internet and MS Exchange server

As a mail relay server, it might be easier to setup a fresh server with Postfix + Amavisd + SpamAssassin + ClamAV. of course you can copy some configurations from iRedMail.

The mail flow is clear: postfix receives email, then pipes them to Amavisd, Amavisd re-injects back to Postfix, postfix forwards to Exchange.

A possible problem is:

*) do you plan to verify valid recipients? if not, you may be not able to reject as many spams as possible before queue. the more emails enter queue, the more system resource you need to process them.

So you may need to configure Postfix to query AD (Exchange) to verify local recipients. Our tutorial may help a little:
http://www.iredmail.org/docs/active.directory.html

iRedAdmin-Pro is not required in your case.

4 Reply by Frankstar

  • Frankstar
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Re: iRedMail as relay server between internet and MS Exchange server

yes, Zhang is right but i don’t like querying Active Directory (in this scenario or for that purpose)  as it’s another overhead and if the server is attacked for whatever reasons, there could be a lot of queries going to Exchange. Importing users every time there are changes on Exchange would be the next improvement.

classic advantages and disadvantages.

5 Reply by Volker

  • Volker
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Re: iRedMail as relay server between internet and MS Exchange server

Sorry for the late reply. Thank you very much for your help and keep up the great product and outstanding support!