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Re: Reuse of TXT : draft-ymbk-dns-choices-00.txt

2004-05-19 00:43:06

On May 18, 2004, at 19:30, Pete Resnick wrote:

So let's say that all SPF TXT records start with "_spf", like "_spf.example.com". Now let's say that I've got a domain that has names like "mail1.sales.example.com", "mail2.sales.example.com", "unix.support.example.com", "mail.marketing.example.com", and that's what a recipient will be using for the SPF lookup. So I want an SPF record that will match "*.sales.example.com". How do I make such a record? I can't use "_spf.sales.example.com", because that won't match "mail1.sales.example.com". I can't use "_spf.*.sales.example.com", because as far as I know the DNS will only match wildcards if they are the left-most component of the domain name. So I either have to put in individual records, or I have to depend on the receiver to work their way up the tree and do queries for "_spf.mail1.sales.example.com", and if that fails use "_spf.sales.example.com", and if that failes use "_spf.example.com" (and probably not try "_spf.com" if that fails, eh?). That stinks. We've got a wildcard mechanism in the DNS for a reason. I'd rather not see us have to hack around it to get the same effect. And I have yet to hear a satisfactory response to the issue.

You do not use TXT, but instead a new RR type.

   paf


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