  Masquerading rules


  We sometimes face difficult problems. Email messages are sent out on
  the Internet with improper return addresses. Too often, there is lit-
  tle we can do, because, for all sorts of reasons, the system originat-
  ing these messages can't be corrected.  Masquerading rules offer a way
  to fix the problem at the mail gateway.

  11..  PPrriinncciipplleess

  You are allowed to define simple transformation rules which will be
  applied to all emails being forward by sendmail. Typically, you
  specify a _f_r_o_m and how this _f_r_o_m should be translated.

  You have some flexibility here. You can translate from:


  +o  One domain to another.

  +o  One user of a domain to another user of another domain.

  +o  Any user of a domain to one user of another domain (weird).

  Here is a presentation of the different fields of a rules dialog.


  11..11..  TThhiiss rruullee iiss aaccttiivvee

  You are allowed to activate/deactivate a rule without erasing it using
  this checkbox.


  11..22..  ffrroomm

  You must enter an email address. Optionally, you may omit the user
  name and only supply the domain name prefixed with the '@' character.
  This means that the rule applies to any user of the domain.


  11..33..  nneeww ffrroomm

  The "from" email address will be rewritten using this field. You must
  again specify an email address. Again, you may omit the user name and
  just provide the domain name prefixed with the '@' character.


  11..44..  CCoommmmeenntt

  Enter a comment to remind you about the reasons you used this feature
  (the masquerading rule). Normally, masquerading rules are used last.
  It is better to fix the problem at the origin.  Unfortunately, this is
  not always possible, for all kinds of very good (and stupid) reasons.


  22..  SSoommee eexxaammpplleess


               from      : @hidden_domain
               new from  : @internet_domain.com


  This rule will translate any mail from user@hidden_domain so they
  originate from user@internet_domain.com


               from      : @hidden_domain
               new from  : joe@internet_domain.com


  This rule will translate any mail from user@hidden_domain so they
  originate from joe@internet_domain.com. I'm not sure why one would
  want to do this.


               from      : joe@hidden_domain
               new from  : info@internet_domain.com


  This rule will translate any mail from joe@hidden_domain so they
  originate from info@internet_domain.com.