Hello,I would like to know what is the best RBLs for Exchange server 2007.We are curerntly using: - Zen.spamhaus.org - Bl.spamcop.net - Dnsbl.sorbs.net But I got many IP addresses blocked from sorbs. What would you suggest? Should I remove sorbs from the RBL?Is that the right thing to do to white IPs or Domains??Thanks

Hi there,You have the better known RBL lists applied. Here's a more comprehensive list: http://www.netwinsite.com/surgemail/help/rbl.htmNote that you can and will get false positives from time to time.If you want insight into how they are performing consider using the provided Get-AntispamTopRBLProviders.ps1There's a good how to here: http://exchangepedia.com/blog/2006/12/exchange-server-2007-how-are-rbls.htmlOliverOliver Moazzezi | Exchange MVP, MCSA:M, MCTS:Exchange 2010, BA (Hons) Anim | http://www.exchange2007.com | http://www.exchange2010.com | http://www.cobweb.com |

Thank you for the useful information Olivier. Idid not see Dnsbl.sorbs.net is the RDL list from the first link u sent me.In fact, I got some users complaining because of IPs being not authorized to by pass our organization.shall I whitelist IP one by one when it happens? or whitelist domains? or remove the Dnsbl.sorbs.net RBL and replace it by another one.What would you all reckon??Graig

Hi,You could add the sender or domain into the WhiteList. However, this can cause the spam email which spoof the addressor the domain youwhitelistcome into the Exchange. Thus, you should enable Send ID to prevent the effect.For more information, please refer to the below article:http://exchangepedia.com/blog/2007/01/exchange-2007-content-filter-whitelist.htmlThanksAllen