Learn the basics
Use the introductory posts on IPs, DNS, ASN, and CGNAT when you want the plain-English explanation before digging into raw outputs.
The fastest way to get value from this section is to combine articles with the tools. Start with a concept guide when you need context, then jump into a live check once you know what signal you want to verify. For example, if you are troubleshooting a VPN, read the privacy or leak guide first, then run DNS and WebRTC checks. If you are working through network ownership or mail troubleshooting, pair the articles with WHOIS, ASN, reverse DNS, and blacklist tools so the learning immediately turns into action.
Use the introductory posts on IPs, DNS, ASN, and CGNAT when you want the plain-English explanation before digging into raw outputs.
Most articles link directly to the tool that proves the point, so you can move from theory to real diagnostics in one session.
When a result is ambiguous, continue into the related guides and follow-up checks instead of relying on one page or one metric.
What a PTR record is, where it lives (in-addr.arpa / ip6.arpa), and when it matters for email and security.
Read ArticleLearn the most common reserved IP ranges: private IPs, CGNAT, loopback, link-local, and documentation blocks.
Read ArticleLearn what reverse DNS is, what PTR records do, and how to find a hostname from an IP address.
Read ArticleA simple explanation of proxy servers, how they work, and what they do (and don't) protect.
Read ArticleLearn what an ASN in networking means, how BGP routing uses autonomous system numbers, and why ASN/ISP shows up in IP tracking tools.
Read ArticleDNSBLs (DNS blacklists) help mail servers stop spam. Learn how they work and why they matter.
Read Article