Blocklist Checker
Check an IP or domain against the major email blocklists in one lookup.
DNSBLs are databases of IPs and domains known for spam. A listing can quietly wreck deliverability. No signup required.
How to use the Blocklist Checker
- Enter an IPv4 address or a domain (we resolve a domain's IPs for you).
- We query the major email blocklists live for each address.
- Review which blocklists, if any, list the target and take action.
Frequently asked questions
A DNSBL is a database of IP addresses and domains known for sending spam. Inbox providers query them, so a listing can quietly send your mail to spam or block it entirely.
We check the major email DNSBLs, including Spamhaus, Barracuda, SpamCop and UCEPROTECT, plus domain-based lists, and report every list a target appears on.
Find and fix the cause of the listing (often compromised accounts or bad sending), then request delisting on each provider's site. Removal times vary from hours to days.
Monitor this automatically
DeliverSignal runs these checks daily and alerts you when something breaks.
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