Masquerading rules Introduction We are sometime facing a difficult problem. Email messages are going out on the internet with improper return address. Much too often, there is little we can do, because the system originating these mes­ sages can't be corrected, for all sort of reason. Masquerading rules offers a way to fix the problem at the mail gateway. 11.. PPrriinncciipplleess You are allowed to define simple transformation rules which will be applied to all email being forward by sendmail. Mostly, 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 · One domain to another. · One user of a domain to another user of another domain. · Any user of a domain to one user of another domain (weird). Here is a presentation of the different field of a rule's dialog. 11..11.. TThhiiss rruullee iiss aaccttiivvee You are allowed to activate/deactivate a rule without erasing it using this checkbox. 11..22.. ffrroomm You must enter an email address. Optionnally, you may omit the user name and only supply the domain name prefixed with the '@' character. This means that the rule apply to any user of the domain. 11..33.. nneeww ffrroomm The "from" email address will be rewritten using this field. You must specify again an email address. Again, you may omit the user name and just provide the domain name prefixed with the '@' character. 11..44.. CCoommmmeenntt Enter whatever you want to remind you of the reason why you have use this feature (masquerading rule). Normally masquerading rules are used last. It is better to fix the problem at the origin. Unfortunatly, this is not always possible, for all kind of very good (and stupid) reasons. 22.. SSoommee eexxaammpplleess 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. 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.