http://www.msexchange.org ------------------------------------------------------- Your thought process is assuming that all SPAM\AV attacks are brute force DOS attacks. Some are some aren't, some attackers still try to guess valid invalid recipients and thus the answer to the question. ________________________________ From: exchangelist-bounce@xxxxxxxxxxxxx on behalf of John T (Lists) Sent: Fri 5/12/2006 6:26 PM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: Drop emails Your thought process is old and no long valid. There have been quite a number of viruses and spam campaigns in the last year that do not care about valid or invalid recipient. They try to force as much as possible. In this sense, part of the intent is to overwhelm and create a sort of DOS attack on the receive system. The sheer volume of messages in those kinds of campaigns far outweigh the obscurity of accepting all then dropping invalid. John T eServices For You "Seek, and ye shall find!" -----Original Message----- From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of ChongJa@xxxxxxxxxxxxxxxx Sent: Friday, May 12, 2006 12:57 PM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: Drop emails Some AV filters will accept all emails for invalid accounts, that way someone attempting to perform a DHA attack cannot determine valid accounts. You can enable recipient filtering but this in itself is susceptible to DHA attacks because the SMTP connection will drop if you specify an invalid account telling you user does not exist or something to that effect. ________________________________ From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of John T (Lists) Sent: Friday, May 12, 2006 3:47 PM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: Drop emails But the question that begs to be asked is why do you want to accept e-mail for invalid accounts in the first place? John T eServices For You "Seek, and ye shall find!" -----Original Message----- From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Bruce J. Rose Sent: Friday, May 12, 2006 10:33 AM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Drop emails Is it possible to have the exchange server accept delivery for invalid accounts and dump them? Thanks Bruce ------------------------------------------------------- List Archives: //www.freelists.org/archives/exchangelist/ MSExchange Newsletter: http://www.msexchange.org/pages/newsletter.asp MSExchange Articles and Tutorials: http://www.msexchange.org/articles_tutorials/ MSExchange Blogs: http://blogs.msexchange.org/ ------------------------------------------------------- Visit TechGenix.com for more information about our other sites: http://www.techgenix.com ------------------------------------------------------- To unsubscribe visit http://www.msexchange.org/pages/exchangelist.asp Report abuse to listadmin@xxxxxxxxxxxxxx