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Re: [anti-spam-wg] New ENISA survey for a study on spam

  • To: adamo@localhost
  • From: Nuno Loureiro nuno@localhost
  • Date: Wed, 3 May 2006 16:41:28 +0100


On May 3, 2006, at 16:27, Yiorgos Adamopoulos wrote:



Nuno Loureiro wrote:
> [ port 25 blocking ]
What I would like to ask you, is how do the several ISPs implement this technique?

We've implemented several variations of this technique:

1. Block all outgoing SMTP traffic that is not directed to our outgoing mail servers- our users were not really happy with this.

2. Redirect all outgoing SMTP traffic to our outgoing mail servers. This was OK, but on virus outbreaks the servers would be under higher load than what they are supposed to be. So,

3. Redirect all outgoing traffice that is not directed to our outgoing mail servers to another server that has stricted rate limits and checks outgoing email for virii (no antispam checks on this server). Complaints are very few.

I guess I misunderstood the point.
I thought it was referring to incoming mail, not outgoing. I mean, reject incoming mail from dynamic IPs from other ISPs.

We didn't block port 25 yet, but we are planning to do it soon. Thanks for your tips they were helpful anyway... :-)

NL

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