# Transaction-level filtering expressions for MercuryS

# Mercury Mail Transport System, Copyright (c) 1993-2007, David Harris.

# This version of the file was prepared for Mercury/32 v4.5

#

# Each line in this file defines a test that MercuryS should apply at various

# stages of the SMTP transaction processing phase of mail delivery. Each line

# has the following general format:

#

#   <Operation>, <"Expression">, <Action>[Action]>, ["Response"]

#

# "operation" can be:

#

#    'H' for an expression applied to the client's "HELO" greeting

#    'D' for deferred HELO processing; these filters will only be

#        applied if the client does not issue a successful AUTH after

#        issuing HELO but before issuing any other command. Otherwise,

#        these filters are the same as 'H' filters. They allow a user

#        on a system that might otherwise be rejected to redeem the

#        connection by authenticating his identity.

#    'S' for an expression applied to the subject line of the message

#    'R' for an expression applied to each SMTP RCPT command

#    'M' for an expression applied to the SMTP MAIL FROM: command

#

# "Expression" is a Mercury regular expression - see the Mercury help on

# mail filtering rules or content control for the format of a Mercury

# extended regular expression. The expression must be quoted, and is

# applied to the entire HELO command.

#

# Action is one or more characters indicating the action MercuryS should

# take when the expression is matched: the first character in the action

# can be one of the following:

#

#    'R' to refuse the transaction and block all subsequent commands

#    'F' to fail the current command only (allow further attempts)

#    'D' to drop the connection immediately with no error response

#    'B' to issue an error response then drop the connection immediately.

#    'L' to log a system message

#    'X' to stop this phase of transaction filtering for this message

#    'S' to suppress all transaction filtering stages for this message.      

#

# The difference between 'R' and 'F' is that 'R' will cause all subsequent

# delivery commands in the session to be refused, while 'F' will only fail

# the current command - other commands may still be permitted.