Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

maximum length of fqdn

2,861 views
Skip to first unread message

nle...@usia.gov

unread,
May 20, 1998, 3:00:00 AM5/20/98
to

hi,

my eyes are burning from looking thru rfc's. what is maximum length of a
fully qualified domain name? what is limit of the labels(?) within the fqdn?

i thought i interpreted the length of labels could be up to 63 and up to 255
labels in an fqdn? that seems very long.

can someone straighten me out and point me to the correct rfc.

thanks

as always an email cc would be appreciated.

-----== Posted via Deja News, The Leader in Internet Discussion ==-----
http://www.dejanews.com/ Now offering spam-free web-based newsreading

Chris van den Berg

unread,
May 22, 1998, 3:00:00 AM5/22/98
to

> my eyes are burning from looking thru rfc's. what is maximum length of a
> fully qualified domain name? what is limit of the labels(?) within the fqdn?

> i thought i interpreted the length of labels could be up to 63 and up to 255
> labels in an fqdn? that seems very long.

Not quite right. I think labels can be 63 octets each, up to 255 octets for a
domain. RFC 2065 says the maximum number of labels in DNS is 127 (but I
couldn't find where this is initially defined).
You can look through, RFC 1034 and 1035, for some of the first hostname
discussions. Otherwise, try RFC 1123, sections 2.1 and 6.1.3.5 for label
and hostname information.
RFC 1912 also has some discussion of host name issues, but it's an
informational RFC, not a defining standard.

Chris

Chris van den Berg
Programmer/Analyst
Communication and Network Services
(510)643-9837 chri...@ack.berkeley.edu
Key fingerprint = 8B 52 10 58 96 40 E8 9A EA 4B E9 27 F2 29 1A A8

Sobald wir an die Moral glauben, verurteilen wir das Dasein.
-Friedrich Nietzsche


Mark.A...@cmis.csiro.au

unread,
May 23, 1998, 3:00:00 AM5/23/98
to

> hi,


>
> my eyes are burning from looking thru rfc's. what is maximum length of a
> fully qualified domain name? what is limit of the labels(?) within the fqdn?
>
> i thought i interpreted the length of labels could be up to 63 and up to 255
> labels in an fqdn? that seems very long.

The maximum numbet of octets is a label is 63. RFC1035.
The maximum number of octets in a domain name is 255
octets. RFC1035

The maximum length of a fqdn, not a hostname, is 1004 characters.
RFC1035
The maximum length of a full qualified hostname is 253
characters. Imputed from RFC952, RFC1123 and RFC1035.

Mark

>
> can someone straighten me out and point me to the correct rfc.
>
> thanks
>
> as always an email cc would be appreciated.
>
> -----== Posted via Deja News, The Leader in Internet Discussion ==-----
> http://www.dejanews.com/ Now offering spam-free web-based newsreading
>

--
Mark Andrews, CSIRO Mathematical and Information Sciences
Locked Bag 17, North Ryde, NSW 1670, Australia.
PHONE: +61 2 9325 3148 INTERNET: Mark.A...@cmis.csiro.au
MOBIL: +61 41 442 9884 UUCP:....!uunet!cmis.csiro.au!mark.andrews

0 new messages