T

T=

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Types for DSN diagnostics

V8.7 and above

Beginning with V8.7 sendmail , notification of successful, deferred, or failed delivery is now done by using DSN (see RFC1891). The T= delivery agent equate provides three pieces of required information to DSN. The pieces are separated by the slash character:

 T=  mta-type/addr-type/diag-type  

The first piece, the mta-type , is later supplied to the Reporting-MTA : DSN header as its first argument:

 Reporting-MTA: dns; here.us.edu   mta-type here  

The second piece, the addr-type , is later supplied to the Final-Recipient : DSN header as its first argument:

 Final-Recipient: rfc822; [e-mail]   addr-type here  

The third piece, the diag-type , is later supplied to the Diagnostic-Code : DSN header as its first argument:

 Diagnostic-Code: smtp; 550 <[e-mail]>... User unknown   diag-type here  

If the P= for a delivery agent is [IPC] , an undeclared mta-type defaults to dns , an undeclared addr-type to rfc822 , and an undeclared diag-type to smtp . For any other P= the default for an undeclared entry is NULL.

In configuring with the m4 technique, the declarations of the T= delivery agent equates are:

 T=X-Phone/X-FAX/X-Unix   fax  T=DNS/RFC822/X-Unix   cyrus, cyrusv2, local, ph, pop, procmail, qpage  T=DNS/RFC822/SMTP   all SMTP and LMTP agents  T=X-Usenet/X-Usenet/X-Unix   Usenet  T=X-UUCP/X-UUCP/X-Unix   all UUCP agents  T=DNS/X-DECnet/X-Unix   mail11  T=X-Unix/X-Unix/X-Unix   prog  

Other than for the local delivery agent, you cannot change these T= defaults. If the need arises, you can, however, copy an existing delivery agent definition and then modify it as outlined in Section 20.3.2.