IP Blocklist Checker
Check any IP address against major blocklists. See your reputation score, location, network details, and reverse DNS in seconds.
Check any IP against major blocklists — no signup required.
What we check
Full IP reputation analysis
A single lookup surfaces everything that affects your email deliverability from this IP.
Blocklist presence
Checked against major email and security blocklists. Even one listing on a widely-used list can cause deliverability to collapse.
Reputation score
A 0–100 score based on historical sending behaviour, spam reports, and blocklist appearances. Below 40 means delivery problems are likely.
Location & network
Country, region, city, ISP, organisation name and ASN — so you can confirm the IP belongs to the right sending infrastructure.
Reverse DNS (PTR)
Checks whether a PTR record exists and maps back to a hostname. Many receiving servers reject mail from IPs with no reverse DNS.
IP Reputation Questions
Common questions about IP blocklists and email deliverability.
Why does my sending IP end up on a blocklist?
IPs get listed for sending spam, having a poor sending reputation, being part of a botnet, or having no reverse DNS record. Even legitimate senders can get listed if a shared IP on their ESP was abused by another customer.
How do I get removed from a blocklist?
Each blocklist has its own delisting process. Most require you to identify the root cause, fix it, and submit a delisting request via their website. The process can take hours to several days. Some lists auto-delist once your IP stops sending spam.
What is a reputation score?
A score out of 100 indicating how trustworthy the IP is based on historical sending behaviour, blocklist appearances, and abuse reports. Higher is better. A score below 40 will likely cause delivery problems.
Does being on one blocklist mean all my email fails?
Not necessarily — receiving servers consult different combinations of blocklists. However, major blocklists (Spamhaus, Barracuda, SORBS) are checked widely and a listing there will cause significant deliverability damage.
What is a PTR record and why does it matter?
A PTR record (reverse DNS) maps an IP address back to a hostname. Many mail servers check that the PTR record exists and matches the sending domain (forward-confirmed reverse DNS). Missing or mismatched PTR records are a common cause of email rejection.
IP reputation is only part of the picture
Even a clean IP can deliver to spam if your DMARC, SPF, or DKIM are misconfigured. Check all three.