spam checks: PTR records, dynamic domain

[blu at vl.com (Tom Metro)]

Bill Horne wrote:
> Since I use a dynamic dns service to receive email on my Debian box,
> I'll ask what happens when forward (A) and reverse (PTR) records don't
> match.

I believe typical practice these days, if PTR records are examined at 
all, is to just check that they exist, not that the returned domain 
matches the domain specified in the SMTP HELO. But I don't know what 
DynDNS specifically implements.


> I don't know why, but some System Administrators
> think that a "dynamic" domain name is prima facie proof of spam.

What identifies your domain as being dynamic? That it is served by DNS 
servers belonging to a dynamic DNS service? The TTL setting?

  -Tom

-- 
Tom Metro
Venture Logic, Newton, MA, USA
"Enterprise solutions through open source."
Professional Profile: http://tmetro.venturelogic.com/

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