From mboxrd@z Thu Jan 1 00:00:00 1970 Mime-Version: 1.0 (Apple Message framework v752.3) In-Reply-To: References: Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <98676E7E-775A-411A-B018-A3D238379E57@ar.aichi-u.ac.jp> Content-Transfer-Encoding: 7bit From: arisawa@ar.aichi-u.ac.jp Date: Sat, 27 Oct 2007 11:51:09 +0900 To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu> Subject: [9fans] detecting spam Topicbox-Message-UUID: db2dd564-ead2-11e9-9d60-3106f5b1d025 Hello, I receive many SPAMS everyday. Most of them are from IP based dynamic FQDN. Therefore detecting SPAM from FQDN is effective. Almost all mails from IP based dynamic FQDN are SPAM. However there are few important exceptions: we have needs to send mails to users of our smtp host from somewhere using DHCP. Plan 9 smtp server supports SMTP-AUTH so that legitimate users are allowed to transfer their mails to other smtp server. We can also send mails to users of our smtp host using SMTP-AUTH. However the information(the fact the mail is authenticated) is discarded in delivering mails to mbox. Therefore these mails are confused with SPAM. I think it is worthwhile to put a tag something like: X-Authenticated-User: alice following "Received: from ..." in case that the mail is authenticated by alice. Kenji Arisawa