Rule sets are declared in the configuration file by beginning a line
with the letter
Rule sets are identified either by
When identified by name, a number is internally assigned by
. An optional
and number may
follow a name to force specific association of number to name.
Rule sets numbered 0 through 9 are reserved for
's internal use.
Addresses are rewritten by a specific sequence of rules numbered
0 through 4 (see
Rewrites all addresses to prepare them for entry into the sequence
for rule sets. It usually focuses on the host part of an address
and detects the various forms of the local hostname, so that
local delivery can take place
Undoes any special rewriting done by rule set 3.
Rule set 4 is always last
Selects a delivery agent that determines the
rule sets. It also selects the recipient user (which is separately
rewritten and placed into
) and the recipient host (which
is placed as-is into
Rewrites all sender addresses
Rewrites all recipient addresses
(Not shown in
Can select a new delivery agent (just like rule set 0).
If the address is
matched in the
it is passed to rule set 5. Addresses are given to rule set 5 before
files are processed