Guides to networks and the internet
Straight answers to the most common network problems, with the right tool for each one.
My IPWhat is CGNAT and how to tell if your internet uses itLearn what CGNAT is, why it stops you from opening ports and hosting servers at home, how to check in two minutes if you are behind it, and what to do next.4 min readPing TestHigh ping: causes and how to lower itLearn why ping spikes in games and video calls, how to measure it the right way, and what you can do to lower the latency on your connection.3 min readPort CheckerHow to check if a port is openLearn how to test whether a port is open to the internet, what open, closed and no response really mean, and what to do when it just will not open.3 min readDNS PropagationHow long does DNS propagation takeLearn why DNS changes take time to show up, how long propagation really takes, how to track it, and how to plan a migration with zero downtime.3 min readIs the site down?Is my website down for everyone or just me?Find out in minutes whether a website is down for everyone or only for you, understand the most common errors, and learn what to do in each case.3 min readMy IPThe difference between IPv4 and IPv6Learn what changes between IPv4 and IPv6, why IPv4 ran out, whether your connection already has IPv6, and whether you should care at home or at work.3 min readDNS LookupWhat MX, SPF, DKIM and DMARC records areLearn the DNS records that get your domain's email delivered instead of sent to spam: MX, SPF, DKIM and DMARC, with examples and common mistakes.3 min readReverse DNSWhat reverse DNS is and what it is forLearn about reverse DNS, the PTR record and FCrDNS checks, why they matter so much for mail servers, and how to set them up with your hosting provider.3 min readDNS LookupHow to find the IP address of a websiteSee how to find the IP address of any website from your browser, your computer or an online tool, and learn why it changes or shows up differently.2 min readTracerouteHow to read a tracerouteLearn how to read a traceroute or tracert: hops, times, asterisks, and how to pinpoint where your connection slows down or stops responding altogether.3 min readMy IPStatic IP vs. dynamic IP: which one do I have?Learn the difference between static and dynamic IPs, how to tell which one you have, when a static IP is worth it, and how dynamic DNS can help.3 min readPing TestInternet quality beyond Mbps: ping, jitter and packet lossFind out why fast speeds are not enough: learn to measure ping, jitter and packet loss, which values are good, and what to do when they are bad.4 min read