# A domain-specific form of aliasing, allowing multiple virtual domains to be

# hosted on one machine.

#

# info@foo.com	foo-info

# info@bar.com	bar-info

# joe@bar.com	error:nouser 550 No such user here

# jax@bar.com	error:5.7.0:550 Address invalid

# @baz.org	jane@example.net

#

# then mail addressed to info@foo.com will be sent to the address foo-info,

# mail addressed to info@bar.com will be delivered to bar-info, and mail

# addressed to anyone at baz.org  will be sent to jane@example.net, mail to

# joe@bar.com will be rejected with the specified error message, and mail to

# jax@bar.com will also have a RFC 1893  compliant error code 5.7.0.

#

# The username from the original address is passed as %1 allowing:

#

# @foo.org	%1@example.com

#

# Additionally, if the local part consists of "user+detail" then "detail" is

# passed as %2 and "+detail" is passed as %3  when a match against user+* is

# attempted, so entries like

#

# old+*@foo.org	new+%2@example.com

# gen+*@foo.org	%2@example.com

# +*@foo.org	%1%3@example.com

# X++@foo.org	Z%3@example.com

# @bar.org	%1%3

#

# Note: to preserve "+detail" for a default case (@domain) %1%3 must be used

# as RHS. There are two wildcards after "+": "+" matches only a non-empty

# detail, "*" matches also empty details, e.g., user+@foo.org  matches#

# +*@foo.org but not ++@foo.org. This can be used to ensure that the

# parameters %2 and %3 are not empty.

#

# All the host names on the left hand side (foo.com, bar.com, and baz.org)

# must be in class {w} or class {VirtHost}. The latter can be defined by the

# macros VIRTUSER_DOMAIN or VIRTUSER_DOMAIN_FILE (analogously to

# MASQUERADE_DOMAIN and MASQUERADE_DOMAIN_FILE). If VIRTUSER_DOMAIN or

# VIRTUSER_DOMAIN_FILE is used, then the entries of class {VirtHost} are

# added to class {R}, i.e., relaying is allowed to (and from) those domains.