ISP Directory

The core ISP service is internet access: a connection from your home or business to the provider's network, and from there to the rest of the internet. Providers deliver it over different technologies, and the technology decides most of what you experience: download and upload speed, latency, and how steady the connection is at busy times.

Around that connection, most ISPs bundle related services. You get a public IP address, usually dynamic on home plans, with static IPs sold to businesses. You get DNS resolvers that turn domain names into addresses, a modem or gateway router, and often WiFi equipment. Many providers add email accounts, TV, home phone and mobile plans. Business plans add service level agreements, static IP blocks, and dedicated or symmetric connections.

Two of those services affect your diagnostics directly. Address assignment decides whether you get a public IP of your own or share one behind carrier-grade NAT, which the CGNAT test can confirm. And your ISP's DNS resolvers see which domains you look up unless you change them or use a VPN, which the DNS leak test will show. To see which ISP you are on right now, run an IP lookup or read What is my ISP?

• Cable (DOCSIS): delivered over the coaxial TV network. Fast downloads, much slower uploads, and widely available in the US.
• Fiber (FTTH): the fastest and most consistent option, often with equal upload and download speeds and multi-gig tiers.
• DSL: runs over telephone lines. Speed falls with distance from the exchange, and many providers are retiring it.
• 5G and fixed wireless home internet: a receiver talks to a nearby tower. Easy to install, but speed varies with signal and network load, and many plans use CGNAT.
• Satellite: covers rural areas. Low-orbit services have brought latency down to tens of milliseconds, while geostationary satellite still adds around 600 ms.
• Mobile data: phone carriers are ISPs too, and a phone can share its connection with a laptop through tethering.

Start with an ISP page for provider context, then map a real IP to ASN, verify PTR/WHOIS data, and cross-check reputation if needed.

The ISP directory is most useful when a lookup already gives you a provider name or an ASN and you need broader context. A provider page tells you whether the network is primarily residential, mobile, regional telecom, or backbone infrastructure. That matters because the same public IP can mean very different things depending on the type of network announcing it.

Residential and mobile providers often use shared address space, dynamic assignment, or CGNAT. In those environments, location data may be approximate and reverse DNS can be generic. Backbone and transit providers, on the other hand, are more likely to appear in traceroutes or routing context without being the final consumer-facing ISP. The directory helps you frame those differences before you decide whether a result is expected, suspicious, or simply incomplete.

These hub and provider pages work best as interpretation layers, not as standalone proof pages. Use them together with live tools like IP location, ASN, WHOIS / RDAP, reverse DNS, and blacklist checks so you can compare provider identity, routing behavior, hostname patterns, and reputation signals in one workflow.

• Open the matching ISP page after you identify the provider or ASN.
• Use the ASN links to confirm which network family announces the range.
• Compare reverse DNS and WHOIS / RDAP before making ownership claims.
• Add blacklist and DNS checks when you are troubleshooting mail or abuse cases.