Written by Martin Wendel, ITS, Uppsala university. Martin.Wendel@its.uu.se


It is not a very good idea to mess with the input of your MTA except when the messages to be converted is sent through a channel only used by those messages. This could for example be when you need to do message conversion for a site connected with an UUCP channel or if you do conversion only for users on the local host.

There are two methods of doing this: (1) Replacing the sendmail binary or (2) replacing the program used to run sendmail. In both methods you move the original program to another location and put Emil at the old location instead. You then force Emil to call sendmail at the new location. This is easiest done using a script calling Emil with the "-m sendmail" flag. This refers to the sendmail mailer as defined in Emil's configuration file emil.cf. Thus, you need to have this mailer correctly defined in advance (it should be, if using the emil.cf provided with the source). Make extensive tests to insure that it works before you move sendmail.

If emil is invoked as sendmail, it will parse arguments according to:

sendmail -f sender recipient

This is the way sendmail is called by mailer agents. Emil will also run as if the arguments mxhost and mailer had been set to localhost and sendmail respectively.

The procedure for making all local programs call Emil instead of sendmail is:

  1. Modify the sendmail mailer in emil.cf to call sendmail.new instead of sendmail.orig. (the original location is referenced sendmail.orig and the new location sendmail.new)
  2. Locate the sendmail binary (usually /usr/lib/sendmail or /usr/sbin/sendmail).
  3. Rename the sendmail binary
  4. Make a symbolic link from sendmail.orig to Emil or rename Emil to sendmail.
You should also change all links pointing to sendmail.orig to point to sendmail.new. This can be such programs as mailq and newaliases aswell as links named sendmail at other locations.

On AIX the procedure would be:

  1. Modify the sendmail mailer in emil.cf to look like:
    mailer sendmail : /usr/sbin/sendmail.orig, sendmail.orig, -f, $s, $r ;
  2. mv /usr/sbin/sendmail /usr/sbin/sendmail.orig
  3. ln -s /usr/local/bin/emil /usr/sbin/sendmail
  4. rm /usr/sbin/mailq; ln -s /usr/sbin/sendmail.orig /usr/sbin/mailq
  5. rm /usr/lib/sendmail; ln -s /usr/sbin/sendmail.orig /usr/lib/sendmail
  6. rm /usr/sbin/newaliases; ln -s /usr/sbin/sendmail.orig /usr/sbin/newaliases

March 1996

ITS Uppsala university
Box 887
751 08 Uppsala

Martin Wendel E-Mail: