Jason, I can't speak for anyone else here, but my opinion of ADSL Ips sending e-mail directly to my servers is that it should be shot on sight. At best, maybe .1% of mail coming directly from ADSL connections is legitimate, and I'm being extremely gracious with that number.
Yes, it is possible to have a "legitimate" mail server set up on an ADSL line with a subscriber network RDNS. It is also theoretically possible to host a "legitimate" mail server on a dial-up connection, on an open proxy, on a server with an open relay or on an IP range in China that has been blacklisted by every single DNSRBL in the universe. There are all kinds of remote possibilities. I draw the line when 99.9%+ of the traffic is spam. At least with Imgate the odd legitimate sender receives notice of the delivery failure, unlike with Scott's weighting system. Anyone who goes the cheap route and routes all of their e-mail via a single MX on an ADSL connection without bothering to configure RDNS is truly getting what they pay for. If a company can't justify the money to spend on at least getting a dedicated SDSL circuit or fractional T1, then they really need to rethink their IT strategy. William Van Hefner Network Administrator Vantek Communications, Inc. > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Jason Loven > Sent: Thursday, March 24, 2005 5:11 AM > To: [email protected] > Subject: RE: [IMail Forum] reverse DNS > > > I'd have to disagree strongly with your characterization of > ADSL as not hosting class. Many of our customers simply > choose not to spend $500-900/month to connect to the internet > and choose to spend $100/month for xDSL. Many are small > businesses running Microsoft SBS (Exchange). I understand > very well the spam dilemma as we do managed email hosting > here and I struggle with this very issue daily. I've chosen > to front-end my systems with ASSP which unfortunately of late > is not handling spam as well as it had up to about a month > ago. BUT I digress...to blanket exclude DSL connections as > "not hosting class" certainly puts an unfair burden on the > huge number of small businesses out there. Heck I pay for > business class cable at home for $80/month but my provide > wont offer rdns at that price/package point. I'm still static > IP though and I host my own email. It's properly configured > and does not spam. Why should I be excluded? > > -----Original Message----- > From: Kevin Bilbee [mailto:[EMAIL PROTECTED] > Sent: Wednesday, March 23, 2005 5:42 PM > To: [email protected] > Subject: RE: [IMail Forum] reverse DNS > > We block on RDNS a message is automatically held if adsl is > in the rdns. We do have exclusions for our RDNs filter like > .SIP. and other exclusions are added only if the email is > materail to our business or clients business. > > Many I have spoken to do not reguard ADSL as hosting class > internet connections. They are mainly for client > connectitivity not not for mail servers or for web servers. I > have had many a client that started using ADSL for their mail > then the spammers hit and the connection became unusable for > even surfing. > > > Kevin Bilbee > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] Behalf Of Scott Perry > > Sent: Wednesday, March 23, 2005 1:44 PM > > To: [email protected] > > Subject: Re: [IMail Forum] reverse DNS > > > > > > > > >65.81.91.10 is the outbound address. .11 is inbound. > > > > > >Also, these are static. Should static addresses be an > exception? We > > > >aren't acting shifty like dynamic addresses. > > > > That's exactly the problem. :) Any spam database that claims to > > block dynamic IPs (which is what this one is apparently doing) that > > lists static IPs is broken. It's no different than a spam database > > that claims to only include IPs belonging to hardcore spammers that > > happens to include an AOL IP. It's an error (incorrect listing). > > > > "adsl-065-081-091-010.sip.cha.bellsouth.net" has the numbers in it > > that make it appear to be a reverse DNS entry that belongs > to an ISP > > -- and therefore to the ignorant assumed to be a dynamic/dialup IP. > > > > Of course, there is no logic to assigning something like > > "adsl-065-081-091-010.sip.cha.bellsouth.net" to a dynamic IP and a > > completely different format (perhaps > > "adsl-12345.sip.cha.bellsouth.net") to static IPs. So the > numbering > > scheme shouldn't be able to identify dynamic IPs (it's much > better at > > identifying non-vanity reverse DNS entries). And I'm guessing that > > ".sip." indicates "static IP", so it sounds like your ISP has done > > their job correctly. > > > > So the short version is that whoever you are trying to send > E-mail to > > is using poor anti-spam software (that is blocking E-mail > on a single > > criterion) that is using a poor anti-spam database (one > that lists IPs > > > erroneously, like MAPS-DUL). Combine the two, and well, you get the > > billion false positives a year. :) > > -Scott > > > > > > To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html > > List Archive: > > http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ > > Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/ > > > > > To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html > List Archive: > http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ > Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/ > > > To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html > List Archive: > http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ > Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/ > To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
