I am running a windows server with Smartermail and SpamAssasin. While I understand what you are telling me below I would really appreciate a suggestion or reccomendation on how to setup a system that will control spam and notify users who's email is blocked in error. Any suggestions or examples you can give would be appreciated. Dan
Bob Proulx wrote: > > dvesely wrote: >> My server manager tells me that my Windows version of SpamAssasin cannot >> reject email at the SMTP level. This is only possibble in the Unix >> version. >> True or False? > > False but for a different reason. False because the Unix version of > SpamAssassin can't reject at the SMTP level either. SpamAssassin is > not an MTA and does not transfer mail with SMTP. An MTA (mail > transfer agent) such as the classic old Sendmail or the newer Postfix > and Exim programs use SMTP to transfer mail from host to host. These > could be MS-Windows but are usually Unix or GNU server machines. > Usually on MS-Windows the MS-Exchange program is used. Only those > programs can reject at the SMTP level. > > If the address is to an invalid address then the MTA has the > capability to know immediately if the message should be rejected. It > can't deliver it and therefore it should not accept the message. This > has nothing to do with spam. This only has to do with valid addresses > and being able to successfully deliver the message. If the message > can't be delivered then it needs to be rejected. > > In the old days (and sadly today on some large organization site) > border machines would receive the message and route the mail through > multiple hops to a final destination machine. At the final > destination it might be undeliverable. In that case a bounce message > is generated and returned to the specified from address. This has > been used by spammers in the past to bounce their spam to their > victims. They create a known invalid address as the recipient at a > site known to create bounce messages after having accepted them. They > forge a victim address as the from address. The message can't be > delivered and the bounce message then carries the spam payload message > as a bounce reply to the forged victim from address as backscatter. > Also known as a joe-job. > > As an additional (newish) capability people want to be able to reject > spam immediately at SMTP time too. In order to do that many people > have added plugins to the MTA (aka milters [mail filter]) to examine > the message at the time of transfer and make an immediate decision > before the SMTP accept as to whether the message is to be accepted or > rejected. If the message is classified as spam by the plugin then the > MTA can reject the message at that time. Using virus scanners and > SpamAssassin as a plugin to the MTA to do this is quite popular. > > But SpamAssassin itself is not doing any of the bouncing. It is > solely the responsibility of the MTA, perhaps based upon input from > these plugins. If you don't have control over your MTA then you do > not have the option of doing this. In which case you should only > silently quarantine or silently discard messages classified as spam. > > Bob > > -- View this message in context: http://www.nabble.com/Bounce-notification-tp14432035p14462333.html Sent from the SpamAssassin - Users mailing list archive at Nabble.com.
