grey-listing

因為今天收到系上某個老師寄來的信, 他在信中還是在抱怨 mail spam 很多.

系上用的 mail server 已經採用 3 個 DNSBL ( SpamCop , Spamhaus , ORDB ) , SpamAssassin , 並擋除 ADSL 浮動 IP 的寄信權 ( SMTP Auth 過關才能寄 ) .
但是根據觀察的結果, 這些好像還是不太夠, 所以剛剛增加了 grey-listing 的機制, 希望能再減少廣告信的量.

一邊裝一邊亂逛網頁時看到這個: Sendmail Milter Softwares from Snert , 裡面列了一些 sendmail 能用的 milter 軟體.

另外, 在 FreeBSD ports 底下也有一些, 我在這邊整理起來備查.

• kavmilter – Sendmail antivirus filter, based on Kaspersky Antivirus and Milter API.
• milter-7bit – A mail filter that tags or rejects email that fail to adhere to proper transfer encodings.
• milter-ahead – A call ahead milter that allows a gateway to verify recipients with an internal mail store before accepting mail.
• milter-bcc – A utility milter that can Bcc: a mailbox for mail to/from particular users and/or domains.
• milter-bogom – Simple sendmail milter to interface bogofilter.
• milter-date – A Sendmail milter that validate a messages”s Received, Resent-Date, and Date headers.
• milter-greylist – Easy-to-use greylist milter for sendmail.
• milter-gris – A Sendmail milter that implements a grey listing techinque.
• milter-limit – Limit the number of messages by connecting client IP, from a sender, or to a recipient over a given time period.
• milter-regex – Milter plugin to sendmail for regular expression filtering.
• milter-siq – Tag, reject, or discard mail using a SIQ reputation server. Based on the Internet Draft for the SIQ Protocol.
• milter-sender – A Sendmail milter that checks in real-time if a sender”s mailbox is in good standing before accepting the message.
• milter-spamc – Yet another Sendmail milter that interfaces with SpamAssassin”s spamd daemon.
• rbl-milter – A milter that adds mail header warnings on mail from open-relays.
• sccmilter – Sendmail spam control and canceling filter, based on Milter API.
• spamass-milter – Sendmail Milter (mail filter) for SpamAssassin.
• spamilter – A Sendmail LibMilter filter to block spam.