OT Routing problem MS sendmail and exchange {Scanned by HJMS}

Dan Farmer dan.farmer at PHONEDIR.COM
Tue Oct 14 16:20:43 IST 2003

On Tuesday, October 14, 2003, at 08:34  AM, Carl Boberg wrote:

> Hi,
> Thank you very much for your reply. Just to clarify some:
> Mailscanner servr has 10 MX (mailgateway)
> Sendmail server  no MX (pop/IMAP)
> Exchange server  no MX
> Exhange recives all mail comming in from the MailScanner and if the
> user at domain.com does not resolve it will forward it to the Sendmail 
> server.
> As it will with all email it cant resolve.
> When a user on the Sendmail server want to email a user on the Exchange
> server the Sednmail just says 550 user unknown.
> Maintaining the alias file on the Sendmail can work but then I will 
> have to
> add aliases there for every new user I get on the Exchange (users that 
> are
> totally new) and change it for users i migrate.
> This is a bit too much administation from my point of view and also it 
> has
> the potential of getting really messy. Who is where and what aliases 
> and so
> forth...
> We are understaffed and under funded so an email admin is not really
> possible :-(

Be aware that what you ask will cause routing loops for any unknown 
users, as both systems will forward and neither will bounce until a 
routing loop is detected, and I'm not sure how many bounces need to 
occur for exchange or sendmail to detect a routing loop - or if they 

You can try the following, I'm not sure if it will work with local 
users on the sendmail box, but I assume it will. Add the following to 
your sendmail.mc file: (tabs where appropriate, change ex.domain.com to 
the proper address, and make sure the exchange server will accept mail 
addressed to user at ex.domain.com)

Mmail1,         P=[IPC], F=mDFMuXa8, S=EnvFromSMTP/HdrFromSMTP, 
R=EnvToSMTP, E=\r\n, L=990,
                 A=TCP ex.domain.com

# These lines are added in this exact location..just above the
# short circuit label.
## Sending mail w/o a dot or underscore to ex.domain.com
R$* < @ $=w >          $#mail1 $@ ex.domain.com $: $1 < @ $2 >
R$* < @ $=w . >        $#mail1 $@ ex.domain.com $: $1 < @ $2 . >

Like the others who have made suggestions, I suggest you don't use 
this, but you bite the bullet and just use the alias file or one of the 
other suggestions until you have completed migrating all users.


> Any more suggestions are very welcome.
> Best regards
> --------------------------------
> Carl Boberg
> System & Network Administrator
> Swedish Museum of Naturalhistory
> Frescativägen 40
> 104 05 Stockholm
> Sweden
> Tel nr: 08-5195 5116
> Mobile: 0701-82 4055
> E-mail: carl.boberg at nrm.se
> --------------------------------
> -----Original Message-----
> From: MailScanner mailing list [mailto:MAILSCANNER at JISCMAIL.AC.UK]On
> Behalf Of Furnish, Trever G
> Sent: den 14 oktober 2003 16:00
> Subject: Re: OT Routing problem MS sendmail and exchange {Scanned by
> So during your transition process you are trying to host the same 
> domain on
> two servers, each of which only has some of the valid users for that 
> domain?
> That won't work -- or at least it's a very odd way of doing things.
> And maintaining a list of which users have been moved and which ones 
> haven't
> is "too much administration"?  If maintaining a list of users is too 
> much
> work for you, then hire an email administrator and stop trying to do it
> yourself.  Successfully migrating from one mail system to another is a
> process that should be undertaken by someone willing to be extremely 
> careful
> and extremely thorough.
> But in the spirit of being helpful, I'll offer this suggestion: give 
> your
> exchange server its own subdomain and use sendmail's virtusertable to
> forward mail to the users migrated to exchange.
> In greater detail:
> Let's imagine that your original domain is foo.com, and that your 
> sendmail
> server is sm.foo.com and your exchange server is ex.foo.com.
> You originally had MX records that looked like this:
> foo.com.        IN MX   10 sm.foo.com.
> Given that starting point, what you should have done was to assign a
> subdomain to the exchange server before moving your users there.  For
> example, you could assign mail.foo.com to the exchange server:
> mail.foo.com.   IN MX   10 ex.foo.com.
> Then, when you create a mailbox on the exchange server, you assign 
> BOTH the
> user's original @foo.com address AND a new @mail.foo.com address.  
> Exchange
> will happily accept multiple smtp addresses for the same mailbox.  Be 
> sure
> that you set the @foo.com address as the mailbox's primary address -
> otherwise when the user sends email it will go out as something else.  
> For
> example, Joe Shmoe's new mailbox on the exchange server would have two 
> smtp
> addresses (as well as all the other addresses exchange creates):
> joe.shmoe at foo.com   <-- set as primary
> joe.shmoe at mail.foo.com
> Now, on your sendmail system all you have to do is forward users as 
> you move
> them.  You can do this with aliases or with the virtuser table, 
> whichever is
> appropriate for your set-up.  If you're using aliases, then on the 
> sendmail
> server you would have an alias of:
> joe.shmoe:      joe.shmoe at mail.foo.com
> After moving a user mailbox you should forward and clear the user mail 
> spool
> on the sendmail server - then you will be able to spot any email still 
> being
> delivered to the user's spool.  If there is still mail flowing into the
> spool of a forwarded user, then he has an address that you have missed 
> -
> just forward that one as well.
> When you have moved *all* users off of the sendmail server, then you 
> can
> take foo.com out of the sendmail server's list of local domain names
> (/etc/mail/local-host-names or /etc/mail/sendmail.cw) and add a RELAY 
> line
> to the sendmail access file for the domain (assuming you still want to 
> use
> the sendmail server as a relay for it).  Then you also need to update 
> DNS to
> direct email to the exchange server directly, so you might end up with:
> foo.com.        IN MX   10 sm.foo.com.
> foo.com.        IN MX   5 ex.foo.com.
> If you intend to use the sendmail system as a mailscanner gateway for 
> the
> exchange server, then you also need to prevent email from flowing 
> directly
> to the exchange server without first hitting the sendmail server.  If 
> your
> exchange server is on windows server 2003 you can probably just reject
> connections to port 25 from everything EXCEPT sm.foo.com.  If you have 
> an
> earlier version of windows then you probably want to use sendmail's
> mailertable or smarthost feature instead.
> HTH,
> Trever
>> -----Original Message-----
>> From: Carl Boberg [mailto:carl.boberg at NRM.SE]
>> Sent: Tuesday, October 14, 2003 8:32 AM
>> Subject: OT Routing problem MS sendmail and exchange {Scanned by HJMS}
>> Hi,
>> I have been looking everywhere fo a solution to this.
>> Using Malscanner a mailgateway (lowest MX)
>> In the DMZ i have a sendmail sever my users connetct to for
>> I now have a new Exchange server and new users on this one
>> and migrating old
>> users
>> slowly from the sendmail to the exchange.
>> MS smtpGW scans all mail comming in an the sends all mail to the new
>> Exchange server.
>> All email the exchange server cant resolve it sends to the
>> old sendmail
>> server (even @domain.com addresses)
>> But the sendmail will only deliver @domain.com if there exist
>> a local user.
>> I need to figure out how to make sendmail deliver local
>> addresses and those
>> @domain.com adresses it doesnt have localy sould be sent to
>> the exchange
>> server?
>> How to solve when a local domain (@domain.com) address has
>> been moved???
>> I could maintain the aliasses file on the old server but that
>> is way too
>> much administration.
>> Also can I make the Mailscanner Mailgateway relay mail to my internal
>> mailservers on a trial error basis?
>> Incomming mail to @domain.com first try internalmailserver1.domain.com
>> if NDR (non delivery reply) then try internalmailserver2.domain.com
>> Sorry if im unclear or messy in my description.
>> Thanks for any help in advance.
>> Bets regards
>> --------------------------------
>> Carl Boberg
>> System & Network Administrator
>> Swedish Museum of Naturalhistory
>> Frescativägen 40
>> 104 05 Stockholm
>> Sweden
>> Tel nr: 08-5195 5116
>> Mobile: 0701-82 4055
>> E-mail: carl.boberg at nrm.se
>> --------------------------------

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