Fighting SPAM

[mcorbett]

Hello,

Have any mail admins out there had any luck blocking spam by somehow blocking all messages whose sending mail hosts do not resolve correctly to a reverse DNS query? If so, can this technique be done with the Windows 2000 virtual SMTP server, or are you using a third party software solution? Thanks for your help!

-Matt Corbett

 

[mjbianco15]

We're using third party software, CMS Praetor. It has reverse DNS blacklisting as well as a ton of other options.

http://www.cmsconnect.com/

 

[mcorbett]

Thanks for your help and such a quick reply!

-Matt Corbett

 

[mcorbett]

Have you had many false positives with this method?

 

[buddafish]

We are really enjoying Barracuda Spam Firewall - it uses LDAP to be Exchange / AD aware. Spam is almost non-existant on our network now... Bad Mail is almost nil... and I have not missed an important email since putting it on line..

scottie

 

[mjbianco15]

Since upgrading to their latest version of Praetor, we have not had many false/positives...it's definetly less than 1%. We've been very pleased. Praetor also offers the LDAP/AD check which verifies that the email addresses are valid to further help with SPAM.

 

[minxca]

try ORF from vamsoft

 

[buddafish]

no matter what appliance you go with, i would make certain it can do LDAP lookups on AD to verify mail is destined for a valid recipient. i would have never believed how important this feature was until i activated it. wow !