CCDEC UTEXAS CSNET MAILNET
CDLOCAL UUCP BITNET DEC UTEXAS CSNET MAILNET CCNET
CZBITNET CCNET
FA/etc/mailhosts.arpadomains
FB/hostname
FF/etc/mailhosts.bitnet
FG/etc/mailhosts.ether
FH/etc/mailhosts.decnet
FJ/hostname
FL/etc/mailhosts
FO/etc/mailhosts.subnets
FU/hostname
