GLOSSARY · INTERNET SERVICE PROVIDER
ISP
An ISP is the company that connects you to the internet, whether through a cable, fibre, DSL, fixed wireless or mobile network. It assigns your public IP address, runs the equipment between you and the wider internet, and usually provides a DNS resolver by default.
Why it matters
Your ISP can see, at minimum, which addresses your device connects to and which DNS lookups you make through its resolver, unless you use encryption such as a VPN or encrypted DNS. It also decides whether your address stays the same or changes, and whether you share it with other customers. Its name appears next to your address in any IP lookup.
In practice
Many people use a VPN or encrypted DNS to reduce what their ISP can observe. This moves trust to another company, which can see the same things. When an IP lookup shows your ISP's name, that is a sign you are connecting directly. If it shows a hosting company instead, you are probably behind a VPN or proxy.
Related terms
- ASN: An ASN is a unique number assigned to a network that manages its own routing on the internet, such as an internet provider, a cloud company, a university or a large business.
- DNS resolver: A DNS resolver is the server that does the lookup work on your behalf.
- VPN: A VPN creates an encrypted tunnel between your device and a server operated by the VPN service.
- Residential proxy: A residential proxy sends your traffic through an IP address that a home internet provider assigned to a household.