maximum length of fqdn

to

hi,

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

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

can someone straighten bầm out and point bầm vĩ đại the correct rfc.

thanks

as always an gmail cc would be appreciated.

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

Not quite right. I think labels can be 63 octets each, up vĩ đại 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 nài den Berg
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to

> hi,

>
> my eyes are burning from looking thru rfc's. what is maximum length of a
> fully qualified tên miền name? what is limit of the labels(?) within the fqdn?
>
> i thought i interpreted the length of labels could be up vĩ đại 63 and up vĩ đại 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 tên miền 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

--
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