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O'Reilly Article on Spam Defense

Dru writes "Here's an article talking about the details of implementing a network level spam defense with Qmail. It also talks a little about a new site called Trustic which uses a trust system (like Advogato) for nominating spammer/hostile IP's."

2 of 189 comments (clear)

  1. Relying on RBLs by GC · · Score: 5, Informative

    There are many problems with using RBLs to block connections. A very good description can be found here:
    I've found SpamAssassin a fairly good, rather than block messages from RBLs it analysis message content, adds points to messages in RBLs and checks known Spam databases such as Razor and Pyzor. Rules matches are given a score, and messages with a total aggregate score are tagged in the message headers, allowing users to filter these if they want to.
    A main advantage of this method is that no single rule can flag a message as spam, hence legitimate mail sourcing from the badly configured mail relay has a chance of getting through, and in my mind it's probably a particularly bad idea to block any email unless it's actually addressed to you.

  2. Or you could use a better mailer... by SuperBanana · · Score: 5, Informative
    Here's an article talking about the details of implementing a network level spam defense with Qmail

    Or, you could just use Postfix, which:

    • is almost entirely compatible with sendmail. It's pretty much drop-in-and-go.
    • adheres to RFCs(and there's a warning for any configuration option which would violate said RFCs)
    • has builtin anti-spam tools- you can turn on, individually, any of a dozen-plus different checks, such as making sure the claimed hostname in the HELO matches the IP the connection is coming from(you can do this several ways), or that the claimed hostname matches the mail-from user@hostname(ie, if you're coming from spammer.com, you're not gonna be able to claim to be joe@yahoo.com), etc. It's also one builtin command to check an RBL.
    • has a really sharp cookie of an author(the guy wrote tcpwrapper), who isn't widely regarded as an obnoxious twit
    • is completely free

    Personally, I refuse to use any software written by DJB as a matter of principle. The guy flagrantly ignores RFCs because he simply feels like it and arrogantly thinks he knows better(and further that there is benefit to ignoring said RFCs).