[nzlug] (OT) Sorbs etc, was Exim: Limiting outgoing connections on Debian

[Hadley Rich]

On Wednesday 11 October 2006 00:29, Robin Sheat wrote:
> On Tuesday 10 October 2006 23:30, Simon Lyall wrote:
> > c. Greylisting is fairly simple for Spammers to beat and they will beat
> > it when it becomes worthwhile.
>
> It's not trivial for spammers to beat. Think of sending 100,000 emails from
> a bot. You're not going to queue them up for retries any time soon.

I had my first experience with greylisting a while back when I was creating a 
python script to to a daily mailout (opt-in of course) of ~5k emails.

The industry that the company is in appears to use a little greylisting and 
some people were complaining that they weren't getting their newsletter.

After looking at the logs and seeing the problem was greylisting, it took all 
of 5 minutes to implement a retry in the script for it and adds all of 2 
minutes to the daily send (this script does personalisation so is probably 
majorly slower than whatever spammers use).

Also, from what I noticed, it wasn't only on the first email that greylisting 
happened - it was every day.

Greylisting hasn't been a major pain for me so far, but for the mail servers I 
look after, the people behind them would prefer to receive their mail 
instantly than wait around for it.

They are pretty happy with the little spam they get due to minimal checks such 
as reject_invalid_hostname, reject_non_fqdn_hostname and spamassassin.

Cheers,

hads.

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