Exchange 2003, Google DNS, and IMF Connection Filtering RBL Failures
|
From: Chucko on 24 Dec 2009 14:28 Just a quick heads up for those of you trying out Google's new DNS servers (8.8.8.8 and 8.8.4.4). I found that when I used Google's DNS Servers that my Exchange 2003 IMF Connection Filtering RBL's (specifically zen.spamhaus.org) were not always working properly and were allowing spam to pass through. Apparently there is something in Google's DNS service that prevents a propery query to zen.spamhaus.org. Switching to another DNS (Open DNS) corrected the problem for me. I only mention spamhaus because they have a quick and simple test capability: http://www.spamhaus.org/faq/answers.lasso?section=Spamhaus%20SBL#207 It was easy for me to see immediately that the DNS change fixed the problem. If you are using Google's DNS and using the Exchange 2003 IMF you might want to test your RBL's to see if they are working properly.
From: Ace Fekay [MCT] on 24 Dec 2009 15:09 "Chucko" <chucko(a)myrealbox.com> wrote in message news:FF2DDBE2-5935-4213-9AAB-1909DAF267C4(a)microsoft.com... > Just a quick heads up for those of you trying out Google's new DNS servers > (8.8.8.8 and 8.8.4.4). > > I found that when I used Google's DNS Servers that my Exchange 2003 IMF > Connection Filtering RBL's (specifically zen.spamhaus.org) were not always > working properly and were allowing spam to pass through. Apparently there > is something in Google's DNS service that prevents a propery query to > zen.spamhaus.org. Switching to another DNS (Open DNS) corrected the > problem for me. > > I only mention spamhaus because they have a quick and simple test > capability: > > http://www.spamhaus.org/faq/answers.lasso?section=Spamhaus%20SBL#207 > > It was easy for me to see immediately that the DNS change fixed the > problem. > > If you are using Google's DNS and using the Exchange 2003 IMF you might > want to test your RBL's to see if they are working properly. > > I remember reading about this issue with Google, as well. It has to do with the type of DNS servers Google uses. Good you found a work around. -- Ace This posting is provided "AS-IS" with no warranties or guarantees and confers no rights. Please reply back to the newsgroup or forum for collaboration benefit among responding engineers, and to help others benefit from your resolution. Ace Fekay, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003 Microsoft Certified Trainer For urgent issues, please contact Microsoft PSS directly. Please check http://support.microsoft.com for regional support phone numbers.
From: Chucko on 25 Dec 2009 16:17 Yes, as it turns out, the folks at Spamhaus are aware of the problem. From their FAQ: Your DNSBL blocks nothing at all! Check what DNS resolvers you are using: If you are using a free "open DNS resolver" service such as Google Public DNS or Level3's public DNS servers to resolve your DNSBL requests, in most cases you will receive a "not listed" (NXDOMAIN) reply from Spamhaus' public DNSBL servers. Please use your own DNS servers when doing DNSBL queries to Spamhaus. "Ace Fekay [MCT]" <aceman(a)mvps.RemoveThisPart.org> wrote in message news:ul13EUNhKHA.5424(a)TK2MSFTNGP02.phx.gbl... > "Chucko" <chucko(a)myrealbox.com> wrote in message > news:FF2DDBE2-5935-4213-9AAB-1909DAF267C4(a)microsoft.com... >> Just a quick heads up for those of you trying out Google's new DNS >> servers (8.8.8.8 and 8.8.4.4). >> >> I found that when I used Google's DNS Servers that my Exchange 2003 IMF >> Connection Filtering RBL's (specifically zen.spamhaus.org) were not >> always working properly and were allowing spam to pass through. >> Apparently there is something in Google's DNS service that prevents a >> propery query to zen.spamhaus.org. Switching to another DNS (Open DNS) >> corrected the problem for me. >> >> I only mention spamhaus because they have a quick and simple test >> capability: >> >> http://www.spamhaus.org/faq/answers.lasso?section=Spamhaus%20SBL#207 >> >> It was easy for me to see immediately that the DNS change fixed the >> problem. >> >> If you are using Google's DNS and using the Exchange 2003 IMF you might >> want to test your RBL's to see if they are working properly. >> >> > > > I remember reading about this issue with Google, as well. It has to do > with the type of DNS servers Google uses. Good you found a work around. > > > -- > Ace > > This posting is provided "AS-IS" with no warranties or guarantees and > confers no rights. > > Please reply back to the newsgroup or forum for collaboration benefit > among responding engineers, and to help others benefit from your > resolution. > > Ace Fekay, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA > 2003/2000, MCSA Messaging 2003 > Microsoft Certified Trainer > > For urgent issues, please contact Microsoft PSS directly. Please check > http://support.microsoft.com for regional support phone numbers. >
From: Ace Fekay [MCT] on 25 Dec 2009 20:22 "Chucko" <chucko(a)myrealbox.com> wrote in message news:%239v7seahKHA.5380(a)TK2MSFTNGP06.phx.gbl... > Yes, as it turns out, the folks at Spamhaus are aware of the problem. > > From their FAQ: > > Your DNSBL blocks nothing at all! > > Check what DNS resolvers you are using: If you are using a free "open DNS > resolver" service such as Google Public DNS or Level3's public DNS servers > to resolve your DNSBL requests, in most cases you will receive a "not > listed" (NXDOMAIN) reply from Spamhaus' public DNSBL servers. Please use > your own DNS servers when doing DNSBL queries to Spamhaus. > Thank you for posting this info. I hope it helps others when they search for this issue. :-) Acee
From: Russ SBITS.Biz [SBS-MVP] on 26 Dec 2009 16:09
Another reason why I think OPENDNS.com ROCKS :) Free and "WORKS" :) Russ -- Russell Grover - SBITS.Biz [SBS-MVP] Microsoft Gold Certified Partner Microsoft Certified Small Business Specialist World Wide 24hr SBS Remote Support - http://www.SBITS.Biz 30% OFF Microsoft Online Services - http://www.microsoft-online-services.com/ "Ace Fekay [MCT]" <aceman(a)mvps.RemoveThisPart.org> wrote in message news:u32BfnchKHA.5568(a)TK2MSFTNGP02.phx.gbl... > "Chucko" <chucko(a)myrealbox.com> wrote in message > news:%239v7seahKHA.5380(a)TK2MSFTNGP06.phx.gbl... >> Yes, as it turns out, the folks at Spamhaus are aware of the problem. >> >> From their FAQ: >> >> Your DNSBL blocks nothing at all! >> >> Check what DNS resolvers you are using: If you are using a free "open DNS >> resolver" service such as Google Public DNS or Level3's public DNS >> servers to resolve your DNSBL requests, in most cases you will receive a >> "not listed" (NXDOMAIN) reply from Spamhaus' public DNSBL servers. Please >> use your own DNS servers when doing DNSBL queries to Spamhaus. >> > > Thank you for posting this info. I hope it helps others when they search > for this issue. > > :-) > > Acee > > > |