Chapter 25. The H (Headers) Configuration Command

The H (header) configuration file command specifies headers that are required for inclusion in the header portion of mail messages. Some headers, such as Date:, are added only if one is not already present. Others, such as Received: (§25.12.29[3ed]), are added even if one or more are already present.

What’s New with V8.13

One major and three minor changes have been made regarding the handling of headers under V8.13:

  • The $>+ operator no longer balances special characters (Section 25.1.1 [V8.13]).

  • The Message-Id: (§25.12.23[3ed]) header’s value is now stored in the new ${msg_id} macro (Section 21.1.5 [V8.13]).

  • The Delivery-Receipt-To: header used by SIMS (Sun Internet Mail System), is treated the same as a Return-Receipt-To: header (§25.12.33[3ed]). That is, sendmail now converts it to a DSN reply.

  • The confMESSAGEID_HEADER mc macro has been added, which allows you to define a different Message-Id: header value (Section 25.1.2 [V8.13]).

No Balancing with $>+

Recall (§25.5[3ed]) that header values can be passed to rule sets using the $> and $>+ operators:

Hname: $>  
               rule  set
Hname: $>+ rule  set     
               
               
                don't strip comments

Prior to V8.13, the $>+ operator caused a header’s value to be passed to the specified rule set with RFC2882 comments intact:

text (comments)
<address> commment

Also, prior to V8.13, the $>+ operator checked for special balancing characters and performed a correction when they were not found. For example, if a Subject: header’s value ...

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