OpenBSD-4.6/etc/mail/local-host-names

# $OpenBSD: local-host-names,v 1.1 2003/09/23 21:37:11 millert Exp $
#
# List additional hostnames that should be considered local (one per line).
# I.e., any hostname for which you wish mail to be accepted (and delivered).
# You do not need to include the system hostname, localhost, the name(s)
# associated with any active network interface or a CNAME that points to one
# of those names.
# This file is read only at startup or when sendmail(8) is sent SIGHUP.
#