How to check whether spam protection based on spamhaus.org blacklists is working

Created:

2016-11-16 13:25:25 UTC

Modified:

2017-08-08 13:40:35 UTC

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How to check whether spam protection based on spamhaus.org blacklists is working

Applicable to:

  • Plesk for Windows
  • Plesk for Linux

Symptoms

How to check whether spam protection based on spamhaus.org blacklists is working

Resolution

  1. Make sure that the option "Switch on spam protection based on DNS blackhole lists DNS zones for DNSBL service" is enabled in mail server settings.

  2. Try to send mail to the following email addresses from the server you need to test:

    • nelson-sbl-test@crynwr.com - for SBL testing
    • nelson-pbl-test@crynwr.com - for PBL testing
    • nelson-xbl-test@crynwr.com - for XBL testing
  3. Check whether mail got bounced back with message alike:

    554 The IP Address of the sender (192.203.178.138) was found in a DNS blacklist database and was therefore refused.

    The similar can be observed in the maillog :

    Jul  5 15:20:15 servername postfix/smtpd[20719]: NOQUEUE: reject: RCPT from ns1.crynwr.com[192.203.178.14]: 554 5.7.1 Service unavailable; Client host [192.203.178.14] blocked using b.barracudacentral.org; Client host blocked using Barracuda Reputation, see http://www.barracudanetworks.com/reputation/?r=1&ip=192.203.178.14; from=<nelson-expn@crynwr.com> to=<user@domain.tld> proto=SMTP helo=<pdam.crynwr.com>
  4. If you will see that the message from sender nelson-expn@crynwr.com received from IP address 192.203.178.138 are blocked, then spam protection based on spamhaus.org blackhole lists is working fine.

Additional information available on the following resources:

http://www.crynwr.com/spam/

https://www.spamhaus.org/faq/section/DNSBL%20Usage#205

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