NSToolKit
NSToolKit
free network tools
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IP Blacklist / RBL Check

Query over 50 major DNS-based Realtime Blacklists (DNSBL/RBL) to check if an IP address or domain is flagged for spam or malicious activity. Includes Spamhaus ZEN, Barracuda, SORBS, and more.

Checks against 15 DNSBL/RBL lists. Takes a few seconds.