While it's easy to check if a single IP address is blacklisted for SPAM using for example http://www.spamcop.net/bl.shtml, then is there a way to check multiple addresses at once? For example how to check if some of the /22(1022 usable IPv4 addresses), which were used by a customer and now returned to ISP, are blacklisted by SPAM lists or not and if it is fine to give those to another customer?

  • I know a lot of sites perform blacklist check for a single IP address but no website performs scan for multiple IP address at a time because this will consume server resources
    – Ahmed
    Dec 29, 2013 at 9:36

3 Answers 3


Spamcop (like other DNSBLs) uses DNS to allow for quick lightweight lookups. Use the DNSBL client of your choosing, or roll your own.

Alternately, you can just contact spamcop and ask them for help. This might be the preferred solution since you have a lot of hosts to look up.

  • How do you use for example rblcheck DNSBL lookup utility? Do you need to specify a special name server or even or will do?
    – Martin
    Aug 7, 2013 at 7:39

Some DNSBL make available full data via rsync for free [e.g. UCEPROTECT, CBL]. https://en.wikipedia.org/wiki/Comparison_of_DNS_blacklists

Bad address are usually listed by many DNSBLs. You may use "full data available" DNSBLs to select addresses for classic "full check" using DNS queries for single IP address single DNSBL.


try robtex; imho the most comprehensive bl-overview

oh, and mtoolbox is nice too.

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