Sendmail Installation and Operation Guide
SMM:08-45
If this ruleset is defined, the option DefaultAuthInfo is ignored (even if the ruleset does not
return a ``useful'' result).
5.1.4.17. queuegroup
The queuegroup ruleset is used to map a recipient address to a queue group name.
The input for the ruleset is a recipient address as specified by the
SMTP RCPT
command.
The ruleset should return $# followed by the name of a queue group. If the return value
starts with anything else it is silently ignored. See the section about ``Queue Groups and
Queue Directories'' for further information.
5.1.4.18. greet_pause
The greet_pause ruleset is used to specify the amount of time to pause before sending
the initial SMTP 220 greeting. If any traffic is received during that pause, an SMTP 554
rejection response is given instead of the 220 greeting and all SMTP commands are rejected
during that connection. This helps protect sites from open proxies and SMTP slammers.
The ruleset should return $# followed by the number of milliseconds (thousandths of a sec-
ond) to pause. If the return value starts with anything else or is not a number, it is silently
ignored. Note: this ruleset is not invoked (and hence the feature is disabled) when the smtps
(SMTP over SSL) is used, i.e., the s modifier is set for the daemon via DaemonPortOp-
tions
, because in this case the SSL handshake is performed before the greeting is sent.
5.1.5. IPC mailers
Some special processing occurs if the ruleset zero resolves to an IPC mailer (that is, a
mailer that has "[IPC]" listed as the Path in the M configuration line. The host name passed
after "$@" has MX expansion performed if not delivering via a named socket; this looks the
name up in DNS to find alternate delivery sites.
The host name can also be provided as a dotted quad or an IPv6 address in square brack-
ets; for example:
[128.32.149.78]
or
[IPv6:2002:c0a8:51d2::23f4]
This causes direct conversion of the numeric value to an IP host address.
The host name passed in after the "$@" may also be a colon-separated list of hosts. Each
is separately MX expanded and the results are concatenated to make (essentially) one long MX
list. The intent here is to create "fake" MX records that are not published in DNS for private
internal networks.
As a final special case, the host name can be passed in as a text string in square brackets:
[ucbvax.berkeley.edu]
This form avoids the MX mapping. N.B.: This is intended only for situations where you have a
network firewall or other host that will do special processing for all your mail, so that your MX
record points to a gateway machine; this machine could then do direct delivery to machines
within your local domain. Use of this feature directly violates RFC 1123 section 5.3.5: it should
not be used lightly.
5.2. D -- Define Macro
Macros are named with a single character or with a word in {braces}. The names ``x'' and
``{x}'' denote the same macro for every single character ``x''. Single character names may be
selected from the entire ASCII set, but user-defined macros should be selected from the set of upper