Re: Directory Harvest Attack

  • From: Danny <nocmonkey@xxxxxxxxx>
  • To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
  • Date: Mon, 6 Dec 2004 13:55:44 -0500

On Mon, 6 Dec 2004 11:55:57 -0200, Tiago de Aviz <tiago@xxxxxxxxxxxxxxx> wrote:
> Hello All, 
> I've been suffering a DHA for the last two weeks. Nothing major, just a
> couple of e-mails per minute, but it is clogging my spam box with all kinds
> of invalid addresses. 
> I've disabled NDR´s so the dude who's sending these things won't be able to
> know which e-mails are valid or not. 
> I´ve tracked these messages and they appear to be coming from all over the
> place. How can I fight it? Disabling NDR´s is not a cool solution because
> people can´t know if a message was delivered here. 

Four options/solutions depending on your budget, time, experience:

1) Sign-up for a managed outsourced Anti-spam/virus service such as:
Postini, MX Logic, Brightmail,etc.

2) Setup your own email anti-spam firewall/gateway system such as:
Postfix on FreeBSD

3) Procure an anti-spam appliance such as: Barracuda spam firewall, xwall, etc.

4) Procure something from GFI for Exchange.


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