[comp.mail.sendmail] PLEASE NOTE: CS is an official top level domain now!!!

piet@NIC.EU.net (Piet Beertema) (12/19/90)

All mail/systems managers please take note that CS is
now an official top level domain. I've already seen
several mails pass by on mcsun.EU.net, which is where
the MX records for .cs point to. All those mails are
doomed to fail, since they weren't really meant for a
host in Czecho-Slovakia, but for an internal host and
resulted from the use of abbreviated addressing of the
form user@host.cs within a domain like cs.foo.bar.
Note that according to RFC822 par. 6.2.2, abbreviated
addressing is bound to restrictions. Hosts that allow
abbreviated addresses that end on a domain name that
is - or may sooner or later be - a top level domain
violate these restrictions. Officially only 2-letter
codes that are listed in ISO-3166 can become top level
domains, but given political reality ISO-3166 won't
last forever and it's safer to *never* use a 2-letter
code for a subdomain.


-- 
	Piet Beertema, EUnet-NIC, Amsterdam   (hostmaster@NIC.EU.net)