OpenBSD-4.6/etc/mail/relay-domains

# $OpenBSD: relay-domains,v 1.2 2003/12/23 21:17:04 miod Exp $
#
# List of other domains to relay mail for here (one per line).
# By default, sendmail(8) will not relay for foreign domains.  If the mail
# is not destined for (or sent by) a user in the local domain the message
# will be rejected.  Alternately, domains may be listed in /etc/mail/access
# with the RELAY attribute instead of being enumerated here.
#
# This file is read only at startup or when sendmail(8) is sent SIGHUP.
#