In message <17812038.7306.1361835383974.JavaMail.root@benjamin.baylink.com>, Ja y Ashworth writes:
----- Original Message -----
From: "Mark Andrews" <marka@isc.org>
No. See RFC 952
I think 952 is functionally obsolete, requireing a <24 char name length; I would have expected citations, perhaps, to 1535.
Care to expand?
Ok. RFC 952 as modified by RFC 1123. This covers all legal hostnames in use today including those that do not fit in the DNS. The DNS supports hostnames up to 253 bytes (255 bytes in wire encoding). RFC 1123 allow hostnames to go to 255 bytes. I'm deliberately ignoring IDN's as they still need to map back into what is permitted by RFC 952 as modified by RFC 1123.
And except on length and first-digit-allowed, 1123 punts naming to 952 (which doesn't really say) and in 6.1, to 1034 and 1035. So I know what my light night reading will be (unless Albitz, Liu, Mockapetris, or any of the BIND team are around on the list :-)
952 says hostnames don't end in a period. Note that periods are only allowed when they serve to delimit components of "domain style names". <hname> ::= <name>*["."<name>] <name> ::= <let>[*[<let-or-digit-or-hyphen>]<let-or-digit>] 1123 turned <name> into <name> ::= <let-or-digit>[*[<let-or-digit-or-hyphen>]<let-or-digit>] it also banned all digit tlds (no covered in the grammar).
RFC 1535 is NOT a STANDARD. Not all RFC are created equal.
Typo. 1035 (as updated by whatever is on-point, if anything).
And 1035 refers you to 952 + 1123 for hostnames. However, when assigning a domain name for an object, the prudent user will select a name which satisfies both the rules of the domain system and any existing rules for the object, whether these rules are published or implied by existing programs. For example, when naming a mail domain, the user should satisfy both the rules of this memo and those in RFC-822. When creating a new host name, the old rules for HOSTS.TXT should be followed. This avoids problems when old software is converted to use domain names. HOSTS.TXT == RFC 952. Host names and domain names are not interchangable in all contexts. You need to know the subtle differences and when which rules apply. Lots of rfcs fail to make the proper distinctions and use domain name when they mean domain style hostname. Mark
And Mark: could you please trim your quoting a bit?
Cheers, -- jra -- Jay R. Ashworth Baylink jra@baylink.co m Designer The Things I Think RFC 210 0 Ashworth & Associates http://baylink.pitas.com 2000 Land Rover DI I St Petersburg FL USA #natog +1 727 647 127 4
-- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org