Actually, AOL also is verifying servers by name and could just as easily set up their own db of rDNS to use as a first line filter before checking an outside source. So, any email that comes in from abcxyz.com that has a from IP that matches the one in the verified list gets passed. Only those that don't would be rDNS checked for the dreaded DSL string. AOL would then quit stopping the legit messages and only block zombies. Or, they could fix their system to check for "FIXIP-USERS" and skip those in their blacklist zeal.
Of course, then they would start getting spam from legit email servers that happen to be on DSL and could be people sending out spam (or at least, spam from the point of view of the receiver). Eventually, the publicity of not being able to send to AOL will come out and the effect will be for users to move to another ISP or mail host. As to viruses -- we generally get more forwarded from companies than home users and they don't use DSL. So, your reasoning is pretty faulty as a virus control. Are you also blocking all attachments as a "service" to your users as an anti-virus measure? Karen > From: Joshua Levitsky > > Look at it this way... Many spammers use dialup, DSL, and cable. If a > spammer asks their ISP to change their rDNS then the ISP will wonder what > that customer is up to. If they are a legit business then the ISP > should let > them change it. On the other hand you have zombies and open gateways all > over the internet hanging off dialup, DSL, and cable where the > machine just > sits and spams constantly. The filtering AOL is doing on rDNS > stops -all- of > that spam because those zombies and open relays that are just > machines setup > without much thought won't have rDNS set to something other than the > default. > > Now also think about viruses that are mass mailers. AOL stops > those dead by > this filtering. They can't get in because they have the default rDNS that > has cable, dsl, or dialup in it. That works for us even when a virus is > brand new and in the wild. You can't beat that kind of blocking. > > So now the only spam coming in to AOL is from machines where rDNS has been > setup and one can assume it is a business of some sort. These > people we can > take legal action against and stop their spam. These are about the only > people we actually can hunt down and slap a lawsuit on. > > The spam / virus front is hard when you scale it to millions of customers. 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/
