IP Reputation Checker

Check if an IP address is blacklisted or flagged for abuse. Free reputation lookup against 7 public blocklists with risk scoring.

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APIPOST /api/v1/network/ip-reputation
5(12 votes)
106
checks performed
Try also: Port Scanner
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Key Features

100% Free

No registration required, unlimited checks

Instant Results

Real-time analysis with detailed output

REST API Access

Integrate into your workflow via API

Accurate Data

Live queries to authoritative sources

What is IP Reputation Checker?

The IP Reputation Checker scans any IP address against 7 public abuse blocklists and threat intelligence feeds — including IPsum, AbuseIPDB, FireHOL, and more — to determine whether it has been associated with malicious activity such as spam, brute-force attacks, DDoS participation, malware distribution, or port scanning. The tool provides a risk score from 0 (clean) to 100 (high risk) based on how many blocklists flag the IP and the severity of reported incidents. All lookups are performed instantly using in-memory blocklist data that refreshes every 6 hours for near-real-time threat detection.

This free IP reputation check tool is used by email administrators investigating why their emails are being rejected (the server IP may be blacklisted), security teams evaluating IPs found in server logs or firewall alerts, e-commerce platforms assessing the risk of incoming transactions, hosting providers monitoring their IP space for abuse, and VPN users checking whether their assigned IP has a clean history.

How to Use

  1. 1Enter an IP address or hostname in the input field (your own IP is auto-detected)
  2. 2Click 'Run Check' to scan the IP against all 7 blocklists simultaneously
  3. 3View the overall risk level: Clean, Low Risk, Medium Risk, or High Risk
  4. 4Review the risk score (0-100) and which specific blocklists flagged the IP
  5. 5Check the details for each blocklist hit to understand the type of abuse reported
  6. 6If your IP is flagged, follow the remediation steps provided in the results

Who Uses This

System Administrators

Monitor and troubleshoot infrastructure

Developers

Debug network issues and integrate via API

SEO Specialists

Verify domain configuration and performance

Security Analysts

Audit and assess network security

Frequently Asked Questions

How often are the blocklists updated?
Blocklists are refreshed every 6 hours from 7 public threat intelligence sources including IPsum (aggregated multi-source feed), AbuseIPDB (community-reported abuse), and FireHOL (firewall-oriented blocklists). This means a newly reported malicious IP will appear in our checks within 6 hours of being added to any source list. The in-memory storage ensures instant lookup times with no external API calls during the check.
What does the IP reputation score mean?
The score ranges from 0 (completely clean, not found on any blocklist) to 100 (high risk, flagged by multiple sources for severe abuse). A score of 0-10 means the IP is clean or has minimal risk. 11-40 indicates low risk — the IP appears on one source, possibly a false positive or minor incident. 41-70 is medium risk — multiple sources flag this IP, warranting investigation. 71-100 is high risk — the IP is widely reported for abuse and should be treated with caution. The score considers both the number of blocklist hits and the severity weighting of each source.
Can I check my own IP's reputation?
Yes — your public IP is automatically detected and pre-filled in the input field. Just click Run Check to see whether your IP has been flagged on any blocklists. This is especially useful if your emails are being rejected or landing in spam folders, as a blacklisted IP is one of the most common causes. Regular reputation checks help you catch issues early before they affect email deliverability or access to services that block suspicious IPs.
What should I do if my IP is flagged on blocklists?
First, determine why it was flagged — check the specific blocklist details for the type of abuse reported (spam, brute-force, malware). If you're on a residential connection with a dynamic IP, your ISP may have previously assigned this IP to someone who engaged in abuse. Restart your router to get a new IP, or contact your ISP for assistance. If you're on a server or VPS, check for compromised applications, malware, or open relays that may be generating abuse traffic. Once the issue is resolved, most blocklists automatically delist IPs after a cool-down period (24-72 hours), though some require a manual delisting request.
Does this tool check IPv6 addresses?
The tool accepts and checks IPv6 addresses, but coverage is currently more limited than IPv4. Most public blocklists historically focused on IPv4 because it was the dominant protocol. As IPv6 adoption grows (now over 40% of internet traffic), blocklist IPv6 coverage is improving, but you may see fewer hits for IPv6 addresses even if the IP has been used for abuse. For comprehensive IPv6 threat assessment, combine this tool with other security analysis methods.

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API Endpoint

POST /api/v1/network/ip-reputation
View Documentation