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Re: [dnsext] loads of TXT records for fun and profit

"John Levine" <johnl@taugh.com> Sat, 04 May 2013 04:30 UTC

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Date: Sat, 04 May 2013 04:30:00 -0000
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From: John Levine <johnl@taugh.com>
To: dnsext@ietf.org
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Subject: Re: [dnsext] loads of TXT records for fun and profit
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>> A single TXT record can, of course, contain any number of strings and
>> can be arbitrarily long.  See RFC 1035 sec 3.3.14.
>
>TXT records don't have a specified maximum length, but they cannot be
>arbitrarily long.  They have to fit into an RR.  RDLENGTH, which
>specifies the length of the RDATA field, is an unsigned 16 bit integer
>(max 65535).  See RFC 1035 sec 3.2.1.
>
>64k is very long, but not arbitrarily long.

Well, yes, you're right, the RR's total length is a 16 bit value.  I'd
be pretty horrified if that were ever an issue for SPF.

R's,
John

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