Postfix Users (and Outlook users)

Daniel Maher daniel.maher at
Thu Oct 26 14:57:14 IST 2006

> -----Original Message-----
> From: mailscanner-bounces at [mailto:mailscanner-
> bounces at] On Behalf Of Peter Russell
> Sent: October 25, 2006 5:58 PM
> To: MailScanner discussion
> Subject: Postfix Users (and Outlook users)
> Postfix:
> I was hoping that since there is so many Postfix users using MS we could
> get an updated discussion on what everyone is doing at the MTA level
> with regards to
> a) stopping spam at the MTA
> b) 3rd party anti spam defences - greylisting?

I cannot stress enough how much adding a recipient map to postfix has helped.  Right now, we poll our (Microsoft) Global Directory server once per hour, pull down the entire tree, sanitise the results (there are lots of non-RFC compliant addresses in there) and build a recipient map out of it.  This has been the /single greatest step/ we've taken to reduce the amount of spam our internal Exchange servers have to deal with: down from half a million per day to around 85,000.

We also use the TrendMicro RBL.  Yes, it costs money, but we've found it to be more reliable from a business context.  They're not as zealous, and they actually respond to "false entry" issues in a timely fashion. They don't block quite as much spam as, say, Spamhaus, but they also don't block as much ham accidentally either. :)

 °v°  Daniel Maher
/(_)\ Administrateur Système Unix
 ^ ^  Unix System Administrator
Sentio aliquos togatos contra me conspirare.

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