Re: [IMail Forum] Reverse-DNS-Check

[Matrosity Hosting]

we implemented this by not refusing mail but marking it as spam for the customers to then decide to filter at the client level. Mail is marked as spam by header and subject mod so clients can receive it and decide how they want to handle it. At first clients wanted us to whitelist servers that were not sending them spam but were actually poorly configured without an RDNS entry. Our policy is not to do this but rather educate their mail "admins" about RDNS. I would love to refuse mail based on the lack of RDNS but it would be a hassle since most of these mail "admins" turn out to be business owners running exchange over a cable connection. Chris Martin wrote: Bruce, While agree that AOL is not to be looked at a benchmarker, I like the no RDNS policy. I am doing a little research on the matter and wondered what kind of mail volume you go through in say a day. You mentioned that none of your customers complained. We run a pretty high volume server and would really like to keep BOTH customer complaints and SPAM to a minimum. Any one else that has implemented this policy, please comment as to the success or failure of the policy. Thanks Chris Martin Rapid Systems -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Bruce Barnes Sent: Friday, December 16, 2005 11:21 PM To: IMail_Forum@list.ipswitch.com Subject: RE: [IMail Forum] Reverse-DNS-Check Doesn't matter whether the ISP or the SPAMMER sets up the RDNS. Once we can validate an RDNS, we can prosecute both the ISPs who refuse to stop hosting the spammers as well as the spammers. Either way, RDNS assures a traceable route back to the source, and the ability to prosecute either the spammer AND/OR the hosting company. Illinois, Iowa, Michigan, New York, California, Washington (state), Oregon and Virginia have all successfully prosecuted spammers now, and the prosecution trend will continue to grow as long as mail service providers are willing to start using tools, and maintaining logs, that will allow them to both refuse spam and capture the spammer's information for the purposes of prosecution. We can debate methodology all day long. Until we, as providers, are actually willing to utilize tools in the war against spam, and to either prosecute, or cooperate in the prosecution of spammers, spam will continue to be a very profitable business for the spammers, and a headache for us and our customers or companies. As I said earlier, since our implementation of RDNS checks on all incoming e-mail in February of 2003, none of my customers has ever complained about a single lost message because of my enforcement of RDNS and we will continue to use RDNS as one of the tools in our war against spam no matter what anyone on this list thinks about it. As I stated earlier, AOL already set the threshold on this. See: http://postmaster.aol.com/guidelines/standards.html. While I don't agree with AOL on everything they do, I do agree with them on this one. NO RDNS = REJECTED E-MAIL. Straight to the bit bucket, no notification, no tears, less spam. Bruce Barnes ChicagoNetTech Inc -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Kevin Bilbee Sent: Friday, December 16, 2005 21:43 To: IMail_Forum@list.ipswitch.com Subject: RE: [IMail Forum] Reverse-DNS-Check I did not say the spammers would setup RDNS the ISPs will to avoid problems. Kevin -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Bruce Barnes Sent: Friday, December 16, 2005 7:19 PM To: IMail_Forum@list.ipswitch.com Subject: RE: [IMail Forum] Reverse-DNS-Check If spammers setup RDNS, then they can be more effectively prosecuted under existing laws, something that's already beginning to happen. Bruce Barnes ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Kevin Bilbee Sent: Friday, December 16, 2005 21:04 To: IMail_Forum@list.ipswitch.com Subject: RE: [IMail Forum] Reverse-DNS-Check Then spammer ISP's will setup RDNS for all ip addresses, which most already do! Kevin Bilbee -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Matrosity Hosting Sent: Friday, December 16, 2005 6:47 PM To: IMail_Forum@list.ipswitch.com Subject: Re: [IMail Forum] Reverse-DNS-Check What would happen if everyone refused mail on this test? Bruce Barnes wrote: While it may not be good as a single test, remember that AOL bounces ALL messages without reverse DNS. When one of our bandwidth providers screwed up our reverse DNS allocation, AOL immediately stopped accepting all e-mail from us because our IN-ADDR.ARPA records were no longer available. Once we got the bandwidth provider to re-allocate our REVERSE DNS, AOL immediately started to accept our messages again. For more information on , see: http://postmaster.aol.com/guidelines/standards.html. While AOL's connection message, sent to the mail server as mail transmission to AOL is negotiated states: "America Online (AOL) and its affiliated companies do not authorize the use of its proprietary computers and computer networks to accept, transmit, or distribute unsolicited bulk e-mail sent from the internet. Effective immediately: AOL may no longer accept connections from IP addresses which have no reverse-DNS (PTR record) assigned." The link http://postmaster.aol.com/guidelines/standards.html, in line 4 of the served page, now clearly states: "AOL's mail servers will reject connections from any IP address that does not have reverse DNS (a PTR record)." Considering that one post I saw stated that AOL was rejecting something like eight billion messages per day (please don't attack the quoted number as it may or may not be accurate), based on no reverse DNS entry, that pretty much makes it a "de-facto standard" If they are doing it, then it's going to be pretty hard for others to ignore it. Once we implemented immediate rejection for no reverse DNS entry - two years ago now, we saw our spam drop by almost 50% and have not had one single complaint since doing so. Remember, too, that for anyone to have a reverse DNS entry also requires allocation of the subnet you are using to the primary domain name of your mail server. It CAN be done. Sometimes it takes some work, but it CAN be done. There are several posts in the archive about this very issue. Bruce Barnes ChicagoNetTech Inc -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of John T (Lists) Sent: Friday, December 16, 2005 19:33 To: IMail_Forum@list.ipswitch.com Subject: RE: [IMail Forum] Reverse-DNS-Check It is a good test as part of a weighting system. However, to take action on one test is not so wise. John T eServices For You -----Original Message----- From: [EMAIL PROTECTED] [mailto:IMail_Forum- [EMAIL PROTECTED]] On Behalf Of Martin Schaible Sent: Friday, December 16, 2005 5:16 PM To: Ipswitch IMail Mailing List Subject: [IMail Forum] Reverse-DNS-Check Hi, We do not use the reverse dns check for a spam check. I'm not sure, if the time is right to switch it on. In earlier days, this check was to dangerous. Do you use the reverse dns check? -- Mit freundlichen Grüssen -------------------------------------------- Merlin Consulting Martin Schaible Bahnhofstrasse 27 CH-8702 Zollikon Phone: +41 44 391 30 00 Fax: +41 44 391 32 49 Mail: mailto:[EMAIL PROTECTED] URL: http://www.merlinconsulting.ch Support: http://support.merlinconsulting.ch GPS: N47 20.235 E8 34.226 -------------------------------------------- News - Neue Produkte: .:. NOD32 Antivirus System .:. BlueDragon .:. Kiwi Syslog Monitor .:. Paessler GmbH .:. Sawmill Loganalyzer .:. 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