fixing insecure email infrastructure (was: Re: [eweek article] Window of "anonym

Valdis.Kletnieks at Valdis.Kletnieks at
Thu Jan 13 15:21:20 UTC 2005

On Thu, 13 Jan 2005 12:21:04 +0100, Stephane Bortzmeyer said:

> American bias but remember the Internet is worldwide. I do not know
> how it is in the USA but there are many parts of the world where ISP
> do not have a delegation of and therefore cannot pass it
> to their customers. (It is also common to have many levels of ISP, so
> you need to go through many layers before reaching the RIR.)

That is indeed a problem that needs to be solved if you want any sort of
rDNS-based service to work well.

> Requesting rDNS means "I don't want to receive email from Africa".

Having an rDNS entry for a host doesn't mean you know if it is/isn't in Africa,
to any higher degree of certainty than when you just had the IP address.

I'm not on our campus.  But I can see it from out my office window. (The
official campus starts across the street from me). I'm about 4 hours drive
southwest of Washington DC. is, and has a proper PTR entry back.
It's a host of ours.  It's in Switzerland at our Center for European Studies
and Architecture.

So what did that rDNS entry tell you about its location that you didn't
know from 195.176/16?

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