On Tue, 24 Jul 2012, Stan Hoeppner wrote:
On 7/24/2012 7:13 AM, Morten Stevens wrote:
[...]
Jul 24 12:50:53 mx1 sendmail[32518]: q6OARUOM031928: to=<m...@netbsd.org>, delay=00:23:23, xdelay=00:00:02, mailer=esmtp, pri=332317, relay=mail.netbsd.org. [149.20.53.66], dsn=4.7.1, stat=Deferred: 450 4.7.1 <m...@netbsd.org>: Recipient address rejected: Greylisting in action, please try later
[...]
Greylisting in action, please try later Jul 24 13:50:53 mx1 sendmail[1672]: q6OARUOM031928: to=<m...@netbsd.org>, delay=01:23:23, xdelay=00:00:02, mailer=esmtp, pri=602317, relay=mail.netbsd.org. [149.20.53.66], dsn=4.7.1, stat=Deferred: 450 4.7.1 <m...@netbsd.org>: Recipient address rejected: Greylisting in action, please try later
This is exactly the reason why greylisting is bad.
I'd say, when greylisting isn't set up correctly. One hour and still greylisting the message? Come on...
I have yet to hear of a bot that retries. Thus, there's not reason to set a wait period more than a few seconds, causing the situation above.
Few seconds is much too short. One of our clients has over 20 servers accross the country, with central GL database. Most of them are MX for the domain, and each one is a storage for some subset of emails in this domain. When a spambot tries to deliver a message, goes through all the MXes - so it takes sometimes 20-30seconds for it to get through all of them...
The initial pre-greeting delay is a good idea - although IMHO users definitely should then use submission port (587) without this delay.
For GL, there is no point in setting times larger than few minutes. Bots either don't retry to send email at all, or retry in legit times. On the other hands, most of the spoiled mail servers (usually in larger corporations) do few delivery retries within few seconds and then after many hours...
So far, this client is still satisfied with GL (set to 10 minutes) since it reduces spam amount by around 50% (about 3k messages a day). Sometimes, when we have troubles with some servers - they are simply added to WL. It doesn't happen too often, although this is a typical business - with lots of mailing campanies, emails that sound as if it was a typical spam etc. ;)
Greetings, -- Jacek Osiecki jos...@ceti.pl GG:3828944 I don't want something I need. I want something I want.
