spf-discuss
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Re: Why not just use S/MIME or GPG signatures?

2003-10-07 15:31:49
On Tue, Oct 07, 2003 at 03:36:45PM -0500, Dustin Trammell wrote:
But what if the URL referenced in the TXT record is currently
unavailable?  A better solution might be to use the DNS security
extensions, which provide a mechanism for key distribution, or put the
key IN the TXT record, rather than a URL.

Ref: http://www.faqs.org/rfcs/rfc2535.html

        Thanks for the link!  (Wow, it's a really long RFC!)

        I'm not picky about how the public keys are distributed.  I
chose an URL because:

        * I was not sure the public key would fit in a DNS response.
(I was/am under the impression that (UDP?) DNS data is limited to 512
bytes.  It is very possible that I am wrong about this.  Maybe TCP DNS
is the way to go.)

        * Even if one public key could fit in a DNS record, what if an
MTA uses multiple key pairs?  Would they all fit in DNS?

        Does anyone know how many bytes can be delivered in a TXT
record?

        -Matthew.
______________________________________________________________________
                                                      
matthew(_at_)syrah(_dot_)us

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