I was hoping someone can help me confirm my research. I am correct that domains are now limited to 67 characters in length including the extension? Cheers Ryan
I would consult RFC1035 for the label sizes, but the total length can include multiple labels up to 255 in length. Check section 2.3.4 Jared Mauch
On Jul 23, 2016, at 8:31 AM, Ryan Finnesey <ryan@finnesey.com> wrote:
I was hoping someone can help me confirm my research. I am correct that domains are now limited to 67 characters in length including the extension?
Cheers Ryan
On Sat, Jul 23, 2016 at 08:35:57AM -0400, Jared Mauch <jared@puck.nether.net> wrote a message of 12 lines which said:
I would consult RFC1035 for the label sizes, but the total length can include multiple labels up to 255 in length. Check section 2.3.4
On another mailing list, Marc Blanchet noticed the limit in the RFC is 255 octets, not characters, which make a difference if you use IDN :-)
On 23 July 2016 at 14:31, Ryan Finnesey <ryan@finnesey.com> wrote:
I was hoping someone can help me confirm my research. I am correct that domains are now limited to 67 characters in length including the extension?
63 octets per label (the bits between the period separators) , 255 octets per domain name. In ascii octets and characters are interchangeable, but as Stephan noted, it gets slightly more complicated for IDN.
On 07/23/2016 07:07 AM, Matthew Pounsett wrote:
On 23 July 2016 at 14:31, Ryan Finnesey <ryan@finnesey.com> wrote:
I was hoping someone can help me confirm my research. I am correct that domains are now limited to 67 characters in length including the extension?
63 octets per label (the bits between the period separators) , 255 octets per domain name. In ascii octets and characters are interchangeable, but as Stephan noted, it gets slightly more complicated for IDN.
Not really ... the 1035 limits apply to the A-label
The number of wire octets is <= 255. The number of presentation characters <= 1008 (63*4*3 + 62*4 + 4) In message <5793C61B.4080107@dougbarton.us>, Doug Barton writes:
On 07/23/2016 07:07 AM, Matthew Pounsett wrote:
On 23 July 2016 at 14:31, Ryan Finnesey <ryan@finnesey.com> wrote:
I was hoping someone can help me confirm my research. I am correct that domains are now limited to 67 characters in length including the extension?
63 octets per label (the bits between the period separators) , 255 octets per domain name. In ascii octets and characters are interchangeable, but as Stephan noted, it gets slightly more complicated for IDN.
Not really ... the 1035 limits apply to the A-label
-- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org
On Sat, Jul 23, 2016 at 7:31 AM, Ryan Finnesey <ryan@finnesey.com> wrote:
I was hoping someone can help me confirm my research. I am correct that domains are now limited to 67 characters in length including the extension?
RFC1035; A hostname / FQDN cannot exceed 255 octets in totality. This includes all the label-length fields, therefore, the limit on total human-readable FQDN string is less. (Subtract 1 Octets initially, then subtract more octets for every DNS Path component added, including the Null label at the End of every FQDN.) In addition, the string component of each DNS label is limited to 63 octets. -- -JH
On Sat, Jul 23, 2016 at 11:07 AM, Jimmy Hess <mysidia@gmail.com> wrote:
In addition, the string component of each DNS label is limited to 63 octets.
This is a hard limit in the DNS packet format. In the packet, the dots are replaced by either: 1 byte whose high two bits are 0 and whose low six bits are the length of the next label, 0 to 63. 0 means done, end of the name. 2 bytes, whose high two bits are 1 and whose low 14 bits are the byte offset within the DNS packet where the name continues So what happens is: if there are three names in the DNS packet: www.example.com, ns1.example.com, and ns2.example.com, then the packet will store www.example.com in full (with the dots replaced with the next label length) and then it'll store ns1 followed by a pointer to where "example.com" began in www.example.com and finally it'll store ns2 followed by a pointer to where "example.com" began in www.example.com. Regards, Bill Herrin -- William Herrin ................ herrin@dirtside.com bill@herrin.us Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>
participants (8)
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Doug Barton -
Jared Mauch -
Jimmy Hess -
Mark Andrews -
Matthew Pounsett -
Ryan Finnesey -
Stephane Bortzmeyer -
William Herrin