SMM:08-58
Sendmail Installation and Operation Guide
If the argument vector does not contain $u then sendmail will speak SMTP (or LMTP if the
mailer flag z is specified) to the mailer.
If no Eol field is defined, then the default is "\r\n" for SMTP mailers and "\n" of others.
The Sender and Recipient rewriting sets may either be a simple ruleset id or may be two ids
separated by a slash; if so, the first rewriting set is applied to envelope addresses and the second is
applied to headers. Setting any value to zero disables corresponding mailer-specific rewriting.
The Directory is actually a colon-separated path of directories to try. For example, the defini-
tion "D=$z:/" first tries to execute in the recipient's home directory; if that is not available, it tries to
execute in the root of the filesystem. This is intended to be used only on the "prog" mailer, since
some shells (such as csh) refuse to execute if they cannot read the current directory. Since the queue
directory is not normally readable by unprivileged users csh scripts as recipients can fail.
The Userid specifies the default user and group id to run as, overriding the DefaultUser
option (q.v.). If the S mailer flag is also specified, this user and group will be set as the effective uid
and gid for the process. This may be given as user:group to set both the user and group id; either
may be an integer or a symbolic name to be looked up in the passwd and group files respectively. If
only a symbolic user name is specified, the group id in the passwd file for that user is used as the
group id.
The Charset field is used when converting a message to MIME; this is the character set used
in the Content-Type: header. If this is not set, the DefaultCharset option is used, and if that is not
set, the value "unknown-8bit" is used. WARNING: this field applies to the sender's mailer, not the
recipient's mailer. For example, if the envelope sender address lists an address on the local network
and the recipient is on an external network, the character set will be set from the Charset= field for
the local network mailer, not that of the external network mailer.
The Type= field sets the type information used in MIME error messages as defined by RFC
1894. It is actually three values separated by slashes: the MTA-type (that is, the description of how
hosts are named), the address type (the description of e-mail addresses), and the diagnostic type (the
description of error diagnostic codes). Each of these must be a registered value or begin with "X-".
The default is "dns/rfc822/smtp".
The m= field specifies the maximum number of messages to attempt to deliver on a single
SMTP or LMTP connection. The default is infinite.
The r= field specifies the maximum number of recipients to attempt to deliver in a single
envelope. It defaults to 100.
The /= field specifies a new root directory for the mailer. The path is macro expanded and
then passed to the "chroot" system call. The root directory is changed before the Directory field is
consulted or the uid is changed.
The Wait= field specifies the maximum time to wait for the mailer to return after sending all
data to it. This applies to mailers that have been forked by sendmail.
The Queuegroup= field specifies the default queue group in which received mail should be
queued. This can be overridden by other means as explained in section ``Queue Groups and Queue
Directories''.
5.5. H -- Define Header
The format of the header lines that sendmail inserts into the message are defined by the H
line. The syntax of this line is one of the following:
Hhname: htemplate
H
[?mflags?]hname: htemplate