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Re: DNS gurus: What is the max length of a TXT rec ords?

2004-02-09 08:50:18
No matter what any UDP DNS message can also be a max of 512 bytes ... Thus
the reason for the 255 char limit on TXT records.

Sam

----- Original Message ----- 
From: "wayne" <wayne(_at_)midwestcs(_dot_)com>
To: "SPF discussions" <spf-discuss(_at_)v2(_dot_)listbox(_dot_)com>
Sent: Monday, February 09, 2004 6:57 AM
Subject: Re: [spf-discuss] DNS gurus: What is the max length of a TXT rec
ords?


In 
<5B734AC36BC9714EB88451E6E2F043B1155F48(_at_)alaia01(_dot_)alaia(_dot_)net> 
Marc Alaia
<marc(_at_)alaia(_dot_)net> writes:

Section 2.3.4 limits the length of 'names' to 255 octets, it does not
limit
the length of data fields.

Right.

It is section 3.3 that limits the size of a TXT record.  TXT record use
a <character-string>, and 3.3 defines them as follows:



    3.3. Standard RRs

    [....]                                   <character-string> is a
single
    length octet followed by that number of characters.
<character-string>
    is treated as binary information, and can be up to 256 characters in
    length (including the length octet).


Apparently, I missed this before.


-wayne

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