Network diagnostics, explained
Short, practical guides to the concepts behind our tools — what the numbers mean and how to act on them.
How to Check If a Website Is Down
Is the site down for everyone or just you? A step-by-step way to confirm an outage using ping, HTTP status and DNS checks from multiple locations.
Read guide →What Is Packet Loss?
Packet loss explained: what causes it, how it shows up as lag and stutter, what counts as acceptable, and how to measure it with a ping test.
Read guide →How to Check DNS Propagation
After changing a DNS record, why does it take time to update everywhere? How DNS propagation works, how TTL controls it, and how to check it globally.
Read guide →Understanding HTTP Status Codes
A practical guide to HTTP status codes — what each class (2xx, 3xx, 4xx, 5xx) means, the common ones you'll actually see, and what to do about them.
Read guide →What Is TTFB (Time to First Byte)?
TTFB measures how long until the first byte of a response arrives. What it includes, what's a good TTFB, why it matters for speed and SEO, and how to reduce it.
Read guide →Common TCP Ports Explained
A reference of the TCP ports you'll meet most often — 80, 443, 22, 25, 3306 and more — what each is for, and how to check whether a port is open.
Read guide →How to Diagnose High Latency
Slow, laggy connections explained: what latency is, what causes high ping, and a methodical way to find whether the bottleneck is you, the path, or the server.
Read guide →How Redirect Chains Affect SEO
Redirect chains slow pages and dilute SEO. What a chain is, why 301 vs 302 matters, how chains hurt crawl budget and link equity, and how to fix them.
Read guide →Ping vs TCP Check: What's the Difference?
Ping and TCP check both test reachability but answer different questions. When ICMP ping is enough, when a TCP port check is the real signal, and why ping can mislead.
Read guide →How to Troubleshoot DNS Problems
DNS failures explained: the common causes behind "server not found", how to read A, AAAA, MX, NS and TXT records, and a step-by-step way to isolate the fault.
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