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.
Blog
Practical explanations of how the internet actually works.
- 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.
- 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.
- IP addresses2 min read
Why does my IP address change?
Dynamic leases, router restarts, mobile networks and IPv6 privacy addresses: the everyday reasons your IP isn't constant.
- IP addresses2 min read
Public vs private IP addresses
Why your laptop's address starts with 192.168 while websites see something else — and what that means for connectivity and privacy.
- IP addresses2 min read
CIDR and subnets, explained with examples
What /24 means, how to calculate network and broadcast addresses, and how to split a network into subnets — without memorising tables.
- Privacy2 min read
How IP geolocation works — and why it's often wrong
Location databases don't know where you are. They know where an address block is probably used. The difference matters.
- Routing2 min read
What is an ASN (autonomous system number)?
The internet is about 80,000 independent networks agreeing to carry each other's traffic. Each one has a number. Here's what it means.
- IP addresses2 min read
IPv4 vs IPv6: what actually changes
Address size is the headline, but the real differences are in how networks are numbered, how devices configure themselves, and what happens to NAT.
- IP addresses2 min read
What is an IP address?
The number that identifies your connection on the internet — what it is, who assigns it, and what it does and doesn't reveal about you.