nanog mailing list archives

RE: DNS TXT field usage ?


From: Tarig Yassin <tariq198487 () hotmail com>
Date: Mon, 29 Mar 2010 22:06:08 +0300


Hi Jul

 

Dkim , SPF ,and Domainkey are sender authentication methods for email system. Which use Public Key Cryptography.

 

The mail server apends signiture to every outgoing message using private key. the recepient mail server to verify needs 
the public key which placed in the sender DNS server.  


 

see

 

dig suin.edu.sd txt --> for SPF

dig _domainkey.suin.edu.sd txt  --> for DKIM

 

regards,
-- 
Tarig Y. Adam
Chief Technology Officer
Sudanese Universities' Information Network (SUIN)
T: +249925659149
w: www.suin.edu.sd




 
Date: Sun, 28 Mar 2010 14:04:39 +0200
From: jul_bsd () yahoo fr
To: nanog () nanog org
Subject: DNS TXT field usage ?

Hello,

While watching some parked domains, I recently observed one which has a
TXT field containing some crypto value, something like a ssh key/RSA 512
or 1024 output (only the crypto part 'cvxvcvcxvcxv=' ).

For now, I have referenced the following usage of TXT
- DNS Server information/version
- SPF (format like "v=spf1 a mx -all") [1]
- DKIM (format like "k=rsa\; t=y\; p=MIGfMA0GCSqGSIb3 [...]
YA+OwSMWQIDAQAB", but always in _domainkey.<domain>) [2]
- not DNSSec as I supposed first (only DNSKEY, RR, RSIG, NSEC, not TXT)

Does someone know at what kind of usage this kind of value could
correspond ? (even if, nearly everything is possible)

Maybe somebody knows of a webpage referencing common usage of DNS fields ?
I found http://www.iana.org/assignments/dns-parameters but it points
only on RFC not practical usage.


Thanks a lot.
Best regards,

Jul


[1] http://en.wikipedia.org/wiki/Sender_Policy_Framework
[2] http://www.ietf.org/rfc/rfc4871.txt (7.4)

Note: current RFC referencing TXT field is
http://www.ietf.org/rfc/rfc1035.txt
"TXT RRs are used to hold descriptive text."

                                          
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