Foiling Spammers: Fake SMTP relays - Page 2
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Thread: Foiling Spammers: Fake SMTP relays

  1. #11
    The most effective way to use those valid domain names, ip addresses and phone numbers which spammers can not afford to not to use or fake. Is to build either Mail Server or Mail Client spam filter which goes like this

    ACTION = Reject OR Delete
    ITEM = Body (email body field)
    FUNCTION= Contains String (Sepate with semi-colon)
    String=unihere4d.com;trend455fd.com;redstarbar.co.uk;supersavingsonline.biz;entrye3dd.com;trend455fd.com;1-212-330-8202;

    FROM NOW ON ANY SPAM EMAIL WHICH CONTAINS THOSE DOMAINS WILL BE AUTOMATICALLY REJECT OR DELETED.

    Just imagine if these method would be used in way same way as Anti-virus.

    Norton Anti-Spam

    ->Scan email body for learned span domain names, ip adddresses and phone numbers
    ->When found delete or quarantine
    ->Norton Anti-Spam Updates (Downloads the latest spam domain/IP/Telephone list.

    YOU GET THE IDEA!!!
    smilies are ON

  2. #12
    Senior Member
    Join Date
    Jul 2001
    Posts
    343
    An easy way is for each ISP only allow outgoing mail via their main mail server, all others have to smart relay through it...
    ISP's block Port 25 on it's border router except to it's mailserver so only mail leaving an ISP's
    own network is filtered through it's Mail server.
    This would stop all the SPAM in a matter of days....
    My ISP is set up that way.... and there are at least 7 mail servers on my ISP's system

    My Mailservers all relay outgoing e-mail via my ISP's main mail server
    If a spammer had to do this, it would be real easy to track and
    the ISP would see it happening.....
    Most spammers use cable or ADSL circuits to do their dirty work....
    If the smart relay took off... and ISP's do not want their
    regular customers mail blocked... Guess what would happen....

    I do like to use a free spam blocking software from www.spampal.us and it
    does work well....

    SPAM... Breakfast of Jerks!
    Franklin Werren at www.bagpipes.net
    Yes I do play the Bagpipes!

    And learning to Play the Bugle

  3. #13
    Senior Member
    Join Date
    Jul 2003
    Posts
    114
    Good idea. Another thing to think about is that you've set up a spammer honeypot. I think micky05 is on this tip, but s/he didn't make it explicit. The only people who will connect to your fake relay are people who are trying to use open relays. You could write a little scriptie thing that tried to send mail to abuse@thepersonsisp.com notifying them that they have a probably spammer. Heck, you could keep stats and post to alt.evil.spammers.kill.kill.kill or whatever if an ISP shows a pattern of spamming.

  4. #14
    Jaded Network Admin nebulus200's Avatar
    Join Date
    Jun 2002
    Posts
    1,356
    Just an update, I did wind up writing a fake SMTP server; however, I have only posted it to the Addicts forum. So for all you addicts out there, have a looksee, and for you guys that haven't quite made it yet, maybe you'll have something to look forward to


    /nebulus
    There is only one constant, one universal, it is the only real truth: causality. Action. Reaction. Cause and effect...There is no escape from it, we are forever slaves to it. Our only hope, our only peace is to understand it, to understand the 'why'. 'Why' is what separates us from them, you from me. 'Why' is the only real social power, without it you are powerless.

    (Merovingian - Matrix Reloaded)

  5. #15
    The idea is very good, but the problem is that if they check by sending something to themselves it will not get to them, and they will find another server. Although, as stated it will make them waste time and money finding another server, I have an idea. If you read the first 10 emails, or send them to me to read, so that if they are test emails you can allow those to pass so they think the server is up. Then just kill/dump the mail after you have determined which ones are test mails. You could perhaps write a script to tell.
    -It is I, me-

  6. #16
    Junior Member
    Join Date
    Oct 2003
    Posts
    1

    Thumbs up

    umm...it's very good idea.
    All brain no brawn.

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