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RBL & DNSBL example

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Anonymous
2012-10-17
2013-08-02
  • Anonymous

    Anonymous - 2012-10-17

    Can you provide me/us with an example for the RBL & DNSBL fields:

    • Check Sender IP
    • Check Sender HOSTNAME
    • Check Sender DOMAIN

    And also how to add scores and whitelists.

    The explanation under (i) doesn't explain it enough for me.

    I hope you can provide an example.

    N.B. If you have recommendation for specific RBL and DNSBL-providers I'll appreciate that.

     
  • Marius Gologan

    Marius Gologan - 2012-10-17

    I should say first that I'm not a fan of RBLs.

    Sender IP is weighted, a term used for scoring/balancing. You can find better explanations and examples on google.

    In the past, if one RBL provider was indicating an IP as blacklisted the connection was dropped by the MTA.

    Now, you can combine RBL providers and drop the connection if a certain scoring is met:
    zen.spamhaus.org*3 (if the IP is found, 3 points are added)
    rbl.provider.org*2 (if the IP is found, 2 points are added)
    whitelist.provider.org*-3(if the IP is found, 3 point are decreased)

    The necessary score to reach in order to drop the connection is the number of providers. In our case is 3: (count zen.spamhaus.org & rbl.provider.org & whitelist.provider.org = 3).

    If the IP is found in all 3 providers the total score will be:
    3 (from zen) + 2 (from rbl) + (-3) (from whitelist) = 2.
    The connection will not be dropped.

    If the IP is not found on whitelist, the total score will be 5. The MTA will reject the connection.

    Sender Hostname
    You may use dbl.spamhaus.com (is a Domain block list, not IP)
    Lets take for example and email coming from @gmail.com:
    The hostname appears as xyz.smtp.google.com
    xyz.smtp.google.com will be verified against dbl.spamhaus.org. If is listed, the connection will be dropped.

    Sender Domain
    Similar with the previous example, but gmail.com will be verified instead of hostname (xyz.smtp.google.com)

    For Hostname and Domain verifications I liked Mailpolice, but they no longer exist.
    For the moment, I'll go with Sender IP and ignore the other two (sender hostname and domain).

    Note: before using any Realtime Block List provider, I strongly recommend reading the Terms of Use or License terms. They are free in limited cases.

    Marius.

     

    Last edit: Marius Gologan 2012-10-17
  • Anonymous

    Anonymous - 2012-10-17

    thanks

     
  • Anonymous

    Anonymous - 2013-08-02

    excuseme, i dont understand how i can add to blacklist a IP or domain.

     
  • Anonymous

    Anonymous - 2013-08-02

    You can blacklist sender@domain.com and whitelist @domain.com:
    Create a mailbox on your server.
    Create two folders GOOD/BAD in the mailbox.
    Connect Scrollout > Collector using IMAP.
    Drag and drop emails/spam in GOOD/BAD folders.

     

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