What is IP Due Diligence?
When acquiring IPv4 addresses — whether through purchase, lease, or transfer — performing thorough due diligence is critical. IP Due Diligence is our free tool that consolidates every essential pre-purchase check into a single, comprehensive report.
Instead of visiting multiple websites to check blacklists, BGP announcements, proxy/VPN detection, and WHOIS data separately, you can now enter any IPv4 address or subnet and receive a complete analysis in seconds.
What the Report Covers
1. Blacklist Status
We scan the IP range against 100+ DNS-based blacklists (DNSBLs) to identify any listings. Blacklisted IPs can cause email delivery failures, trigger security blocks, and significantly impact the usability of the address space. The report shows:
- Total IPs scanned vs. blacklisted IPs
- Which specific blacklists flagged each IP
- Blacklist percentage — a key metric for assessing address cleanliness
2. BGP Visibility & Announcement History
Using data from RIPE RIS (Routing Information Service), we analyze:
- Whether the prefix is currently announced in BGP
- Origin AS number and AS name
- Visibility score across global routing peers
- Historical announcement data — which AS numbers previously announced this prefix and when
- AS path diversity and routing stability
3. RPKI Validation
The report checks the Resource Public Key Infrastructure (RPKI) status to determine if valid ROA (Route Origin Authorization) records exist. RPKI validation is increasingly important for BGP security and routing acceptance by major networks.
4. IP Intelligence & Quality Analysis
Each IP in the subnet is analyzed for usage classification:
- Proxy detection — Is the IP associated with open or anonymous proxies?
- VPN detection — Is the IP identified as a VPN exit node?
- Tor detection — Is the IP part of the Tor network?
- Usage type — ISP, hosting, business, education, or other classifications
- Risk score — Overall risk assessment for the IP address
5. WHOIS & Registration Data
Registration information including the current holder, registry (RIPE, ARIN, APNIC), allocation status (Legacy, PI, PA), and organizational details.
Why IP Due Diligence Matters
Buying IPv4 addresses without proper due diligence is risky. Common issues buyers face include:
- Blacklisted ranges — Previous owners may have used the IPs for spam, phishing, or malware distribution
- Proxy/VPN contamination — IPs flagged as proxies or VPNs may be blocked by content providers and financial institutions
- BGP hijacking history — Some prefixes have been used in route hijacking attacks
- Stale routing objects — Old ROA records or route objects can prevent legitimate BGP announcements
A thorough due diligence report helps you make informed decisions and avoid costly mistakes.
How to Use the Tool
- Go to IP Due Diligence
- Enter any IPv4 address or CIDR prefix (e.g.,
185.1.0.0/24) - Click “Generate Report”
- Review the comprehensive analysis
- Download the report as PDF for your records
Free for Everyone
IP Due Diligence is completely free to use. Whether you are buying from IPv4.center or any other provider, you can use this tool to verify the quality and reputation of any IPv4 address block before committing to a purchase.
Every listing on the IPv4.center marketplace also includes a “Download Due Diligence Report” button, so you can instantly access the full analysis for any listing you are interested in.
Try It Now
Stop juggling multiple tools and websites. Get everything you need in one report: IP Due Diligence Tool