Blog — Network Troubleshooting Guides | Check Host
Guides to network troubleshooting: website outages, open ports, traceroute, DNS propagation, ping and IP lookups.
- Is It Down for Everyone or Just Me? How to Check a Website Properly — A website will not load. Here is how to tell whether it is down for everyone, only in your region, or only on your own connection — in under a minute.
- How to Check if a Port Is Open (From Outside Your Network) — Learn how to test whether a TCP port such as 22, 443, 3389 or 25565 is open and reachable from the internet, and how to fix the usual reasons it is not.
- How to Read a Traceroute: Hops, Asterisks and Latency Explained — A plain-language guide to traceroute output: what each hop means, why some show asterisks, and how to spot where a network path actually breaks.
- DNS Propagation Explained: Why DNS Changes Take Time and How to Check — Changed a DNS record and some people still see the old one? Learn how TTL and resolver caching cause "propagation" and how to check it worldwide.
- Ping, Latency and Packet Loss: What the Numbers Mean — What is a good ping? Learn how to read ping results — round-trip time, jitter and packet loss — and what values are normal across the world.
- How to Find the ASN, ISP and Location of an IP Address — Learn what an ASN is, how to look up which network and ISP an IP address belongs to, and how accurate IP geolocation really is.