The following bounce from Comp$Serve violates RFC 1123 5.3.3. They have
been repeatedly informed of this and refuse to fix their mail system.
They also have another problem which their sysadmins refuse to fix (I've
e-mailed them so many times, they just say "well, it works so go away")
-- snip --
$ host compuserve.com
[...]
compuserve.com mail is handled (pri=10) by mailgate.compuserve.com
$ host mailgate.compuserve.com
mailgate.compuserve.com is a nickname for mx3.compuserve.com
mx3.compuserve.com has address 149.174.206.135
mx3.compuserve.com has address 149.174.177.136
mx3.compuserve.com has address 149.174.217.133
mx3.compuserve.com has address 149.174.217.137
mx3.compuserve.com has address 149.174.217.136
mx3.compuserve.com has address 149.174.217.135
mx3.compuserve.com has address 149.174.177.134
mx3.compuserve.com has address 149.174.177.133
mx3.compuserve.com has address 149.174.206.137
mx3.compuserve.com has address 149.174.206.136
-- snip --
*sigh*