[ale] e-mail and virutal domains

Michael H. Warfield mhw at wittsend.com
Thu Nov 21 16:18:53 EST 1996


Jon-Michael J. DeBona enscribed thusly:

> First, I would like to say thanks to everyone who has responded to my
> previous postings about e-mail.  I have one more question.  When a user
> sends e-mail from user at virtualdomain.com to a recipient at any other
> domain on our server, the from field on the mail reads correctly.  If a
> user sends e-mail from user at virtualdomain.com to a recipient outside of
> our domain, the from field reads user@*real*domain.com.  Does anyone
> know how to fix this?  Thanks again.

	This is something in the local/remote address rewriting on
sendmail.  If you have the DM macro set, that is going to cause
sendmail to masqurade as that domain name on all mail heading off
the system.  That's one possibility.  I'm sure that there are others.

	A good recommendation would be to pick up the latest sendmail
version 8.8.3 and install it.  If you go into the "cf" directory you
will find information on how to generate custom cf files using the m4
system.  There is even a "virtusertable" feature for setting sendmail
up to support virtual user mappings.  Looks pretty slick and I haven't
seen it documented anywhere outside of the source package.  That MIGHT
help with this problem.  Then again, it might not, since it's designed
to alias mail addressed TO virtual addresses.  But it might.

	There are lots of bug fixes and security stuff in 8.8.3 as well,
so the recommendation to upgrade is a general one.  In fact, if you have
other users (trustworthy or not) on your systems, you NEED to upgrade
to 8.8.3 to cover an exploit which will allow users to create an SUID
shell for themselves!  Information was on Best of Security and affects
all flavors of sendmail 8.6.x, 8.7.x, and 8.8.x prior to 8.8.3.

	Go to ftp.sendmail.org and change to /pub/sendmail for the sources
and the details.

	Remarks over there indicate that 8.6.x is no longer supported and
should NOT be used on any Internet connected system due to known
vulnerabilities.

> ________________________________________________________________________
> Jon-Michael J. DeBona
> Technical Support Representative         E-Mail:  jdebona at discom.net
> Discovery Communications, Inc.              WWW:  http://www.discom.net/
> 775 Franklin Rd., Suite 100               Voice:  (770) 425-5700 x102
> Marietta, GA 30067                          Fax:  (770) 425-1765
> ------------------------------------------------------------------------
>                Discover a Whole New Internet at Discovery
>              Bringing People Together Through Communications

	Mike
-- 
 Michael H. Warfield    |  (770) 985-6132   |  mhw at WittsEnd.com
  (The Mad Wizard)      |  (770) 925-8248   |  http://www.wittsend.com/mhw/
  NIC whois:  MHW9      |  An optimist believes we live in the best of all
 PGP Key: 0xDF1DD471    |  possible worlds.  A pessimist is sure of it!






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