Privacy2 min read
VPNs and your IP address: what changes, and what doesn't
What websites see with a VPN on, how to check that it works, typical leaks, and what a VPN doesn't protect against.
Blog
Practical explanations of how the internet actually works.
- Privacy2 min read
What can a website see about me?
IP address, headers, browser details and cookies: what is sent automatically, what needs your permission, and what you can limit.
- DNS2 min read
How does reverse DNS work?
Reverse DNS turns an IP address into a name. How the PTR record works, who controls it and why mail servers care.
- Troubleshooting2 min read
How to troubleshoot IPv6 problems
No IPv6 address, IPv6 that exists but doesn't work, or sites that load slowly: a checklist from your device to your provider.
- Routing1 min read
What is BGP routing?
The protocol that ties networks together: prefixes, AS paths, how traffic finds its way, and why RPKI makes the internet safer.
- DNS2 min read
What is DNS propagation, and how long does it take?
Why a DNS change doesn't show everywhere at once, what TTL has to do with it, and how to plan a migration without downtime.
- IP addresses1 min read
What is a subnet mask?
Why 255.255.255.0 and /24 are the same thing, how a mask separates network from host, and what wildcard masks are.
- Routing2 min read
What is an ISP (internet service provider)?
What your provider actually does, where it gets IP addresses, why a lookup may show another name than the brand you pay, and what it can see.
- Privacy2 min read
Can someone find me from my IP address?
What an IP address really says about where you are, who can link it to you, and why 'IP tracing' in films is misleading.
- IP addresses1 min read
How to find your public IP address
The fastest way, and how to find both your public and your private address on Windows, macOS, iPhone, Android and your router.
- DNS2 min read
How does DNS work?
From typing a name to getting an address: resolvers, root servers, TLDs, caching and TTLs, in plain language.
- Privacy2 min read
What is CGNAT (carrier-grade NAT)?
Why your provider may be sharing one public IPv4 address with hundreds of customers, how to tell, and what it breaks.