How to share a SMTP domain between MDaemon and Exchange

exchangemdaemonmigrationsmtp

I need to setup coexistence between MDaemon (13.0.5) and a Microsoft Exchange system (Office 365); the two systems should share the same SMTP domain, and each one should forward to the other any message which has a recipient in that domain but is not local to the server; I already have safeguards in place against routing loops (using a custom header), so this is not an issue.

I have succesfully configured Exchange to route to MDaemon all messages which it can't deliver to its own mailboxes; this works without problems. Now I need to do the same on the MDaemon side.

I configured the relevant options in the "unknown mail" configuration section, but MDaemon keeps rejecting these messages with a 550 error (unknown user).

What am I missing here?

Best Answer

Answer found: you need to configure MDaemon to accept messages addressed to (or coming from) unknown local users, which are by default refused: http://help.altn.com/mdaemon/en/index.html?security__relay_settings.htm.

Account Verification

SMTP MAIL address must exist if it uses a local domain

Click this option is you wish to verify that the MAIL value passed during the SMTP process points to an actual valid account when it is purported to be from a local domain or gateway.

[...]

SMTP RCPT address must exist if it uses a local domain

Click this option is you wish to verify that the RCPT value passed during the SMTP process points to an actual valid account when it is purported to be from a local domain.

Related Solutions

Sendmail’s MTA, MDA and SMTP 550 User Unknown forwarded to postmaster

Turned out to be much simpler than I initially thought. Just ensure you have the following in your sendmail.cf:

FEATURE(access_db, `hash -o -T<TMPF> /etc/mail/access' `relaytofulladdress')
FEATURE(blacklist_recipients)

Note the relaytofulladdress.

Now you can selectively accept specific addresses and reject the rest in access:

Connect:[127.0.0.1]     OK
To:user1@xyz.com        RELAY
To:postmaster@xyz.com   RELAY
To:xyz.com              REJECT

Note the Connect entry to accept local email as well as postmaster@ to accept any administration emails (similar would be for webmaster@ and others if you use them).

Office365 and Active Directory Integration (and On-premise Exchange Disintegration)

The recommended steps at the end of this post can help greatly: http://community.office365.com/en-us/f/156/t/176968.aspx I have not tested it yet as we have some other users that will use the old exchange for now, but it seems pretty promising. This can be done either per user or for the whole system.

To Recap:

Decomissioning the Exchange Server as per MSFT migration instructions does the trick.
Taking the following steps disables autodiscover:
1. Open an elevated Exchange Management Shell and retrieve the current autodiscover virtual directory:
  
  Get-AutodiscoverVirtualDirectory | fl Name, Server, InternalUrl, Identity
  
  Copy the Identity value to the clipboard. Note the internal URL
2. In the Exchange Management Shell, remove the autodiscover virtual directory:
  
  Remove-AutodiscoverVirtualDirectory -Identity ''
  
  You will have to confirm by typing a "A".
3. Check that the autodiscover virtual directory is gone:
  
  Get-AutodiscoverVirtualDirectory | fl Name, Server, InternalUrl, Identity
  1. Internal mailbox records in AD and they may cause issues:
Active Directory Users and Groups > View > Advanced Features

Look at the properties for each user and on the attribute editor tab clear the homeMDB and homeMTA attributes. These are also cleared once the mailboxes are disabled.

Best Answer

Related Solutions

Sendmail’s MTA, MDA and SMTP 550 User Unknown forwarded to postmaster

Office365 and Active Directory Integration (and On-premise Exchange Disintegration)

Related Topic