Complex routing


  Sendmail routes mail using the domain of the recipient.  If Sendmail
  is able to resolve the address to the local user, Sendmail uses the
  recipient's name to finish the job. Sometimes, however, the routing
  decision should be made using both the recipient's name and the desti-
  nation domain.

  1.  Principles

  One reality of the Internet these days is the virtual hosting of
  multiple domains on the same server. This works fine for Web service.
  A single server fakes many virtual servers.

  For electronic mail, sendmail has the ability to accept email for
  multiple domains. Generally, all those domains are aliases (see
  Aliases for your system in basic sendmail configuration) for your
  system. If your system has the following aliases:


  +o  domain1.com

  +o  domain2.com

  then user@domain1.com and user@domain2.com point to the same user
  account and email folder. This may, sometimes, be wrong.  Complex user
  routing can be understood this way:


       If you receive email for one_user@one_domain then forward
       this mail to another_user@another_domain using
       another_email_server.



  2.  Task

  For each rule, you must complete a screen composed of these fields.


  2.1.  This rule is active

  You can deactivate one rule without erasing it. You must regenerate
  the sendmail.cf file and restart Sendmail (linuxconf will tell you to
  do so anyway).


  2.2.  to

  The to field contains the original email destination including the
  full domain name.

  It is possible to redirect a full domain by only entering the domain
  name with the @ character as a prefix (@domain.com). While redirecting
  a domain is normally done with the special domain routing facility of
  linuxconf, using complex user routing allows you to redirect a
  complete domain to a single user account into another domain  (this
  can be very handy!).


  2.3.  Rewritten to

  You must enter the new email destination. If you wish to redirect the
  email to another local user, you can simply enter the user account
  without a domain.
  This looks like a simple alias (see "Setting user aliases"). It is not
  a replacement for aliases; it is more general. For a large user base,
  the normal user alias is more efficient because it uses a database.
  The complex user routing should be used to handle exceptions which
  can't be solved by normal user aliases. For example, normal user
  aliases can't solve this:


  +o  info@vdomain1.com -> joe

  +o  info@vdomain2.com -> jack


  2.4.  Forward to server(opt)

  Normally, Sendmail will find the proper server based on the Rewritten
  to field. Sometimes, you may want to impose a server.  You just write
  the fully qualified name here.


  2.5.  Mailer

  If you specify a server, you must specify the protocol to use.
  Normally esmtp should be used. You can also select uucp-dom when
  forwarding email through a uucp gateway. This is one case where you
  will always specify a destination server.


  2.6.  Priority

  This is just a number used as a hint to sort the rules when generating
  the sendmail.cf file. Higher priority means a rule will be entered
  first in sendmail.cf. This is normally used when two rules intersect
  (one matches a subset of the other). Sendmail matches rules
  sequentially. The first match ends the search.


  2.7.  Comment

  You can write whatever you want here.