2.2 Delivery Agent Equates

The general form of a delivery agent's declaration looks like this:

Mname, equate=val, ...

In this section we list and describe each equate, where only the first letter of each is recognized (that is, Argv= is the same as A=).

A=argv0 argv1 ...

Lists the delivery agent's command-line arguments. The delivery agent speaks SMTP only if $u is absent from those arguments. The special symbolic argv0 names IPC and LPC reference internal sendmail code.

C=ISO-8859-1

Uses the ISO-8859-1 character set in the MIME Content-Type: header (see §30.4.2). Applies to messages received from this delivery agent. Supersedes the DefaultCharSet option.

D=/var/run:/tmp

Sets the paths for execution of the prog delivery agent to /var/run first, and if it cannot chdir(2) into that directory, then to /tmp (see §30.4.3).

E=\r

Specifies the end-of-line characters to be a carriage-return newline pair. Those characters are generated by sendmail for outgoing messages and recognized by sendmail for incoming messages. The default is \r\n for SMTP and \n otherwise (see §30.4.4).

F=flags

Lists flags that describe a delivery agent's behavior (fully listed in the next section, "Delivery Agent F= Flags").

L=512

Limits the length of text lines in the body of a mail message to 512 characters (see §30.4.6).

M=1000000

Limits the total size (header and body combined) of messages handled by the delivery agent to one million characters.

N=5

Says to re-nice(2) the delivery agent by 5 (see §30.4.8).

P=/usr/bin/uux

Says to execute /usr/bin/uux as the delivery-agent program (see §30.4.9). Special symbolic paths can also be used: [IPC] makes a network connection and speaks SMTP; [FILE] appends the message to a file; and [LPC] is useful for tracking down mail problems.

R=rset or R=eset/hset

Lists the rewriting rule set names or numbers for the recipient. A single name or number is applied to both envelope and header rewriting. Two names or numbers, separated by a slash, applies the leftmost to the envelope and the rightmost to headers (see §30.4.10).

S=rset or R=eset/hset

Lists the rewriting rule set names or numbers for the sender. Particulars are the same as for R= above (see §30.4.11).

T=DNS/RFC822/X-Unix

Sets the type tags used in the DSN diagnostic returns for this delivery agent. The type tag for the Reporting-MTA: field is DNS; the type tag for the Final-Recipient: field is RFC822; and the type tag for the Diagnostic-Code: field is X-Unix (see §30.4.12).

U=nullmail:nullgroup

Specifies that sendmail should become the user nullmail and the group nullgroup before executing the delivery agent. If the :nullgroup is omitted, it is found in the passwd(5) file entry for nullmail (see §30.4.13).