IP address reputation, BorderWare

Peter Peters P.G.M.Peters at utwente.nl
Fri Mar 23 09:55:20 CET 2007

Hash: SHA1

Chris Yuzik wrote on 22-3-2007 23:29:
> Gerard Seibert wrote:
>> There was a discussion on the postfix forum a few days ago that concurred
>> with your thesis. I personally never employ it myself. A waste of time
>> and bandwidth in my humble opinion.
> Since we use Sendmail exclusively, I'm afraid I don't follow the Postfix
> forums.
> I'm not sure about the bandwidth, shouldn't be much more than a few
> bytes...perhaps equivalent to a DNS query or two. As for the time delay,
> we're not noticing any delay. According to our logs, most of this
> happens within the very second the mail gets to our server; a fraction
> of a second (or even a couple of seconds) delay is certainly worth it,

It can take a lot of time if spammers start to use domains pointing to
servers that are not responding. Your server will timeout eventually but
it keeps your connections open. It could act as an DDoS against your

- --
Peter Peters, senior beheerder (Security)
Dienst Informatietechnologie, Bibliotheek en Educatie (ITBE)
Universiteit Twente,  Postbus 217,  7500 AE  Enschede
telefoon: 053 - 489 2301, fax: 053 - 489 2383, http://www.utwente.nl/itbe
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