HTTP
7 posts tagged with HTTP.
DNS vs SSL vs HTTP errors: what actually broke?
A broken page can fail at any of four layers — DNS, TCP, TLS, or HTTP. The error message you see almost never names the layer, but the layer is the entire answer. Here's how to tell them apart in under a minute.
Cloudflare error codes: 520, 521, 522, 524, 1015, 1020 decoded
Cloudflare error pages own their own numeric range — 5xx for upstream problems, 1xxx for client-side policy hits. Each code points at a specific failure in a specific place. Here's the field guide.
What `429 Too Many Requests` actually means, and how rate limits really work
Most rate-limit explanations stop at 'you went too fast.' That's true but not useful. Real rate limiters work in five different ways — token bucket, leaky bucket, fixed window, sliding window, concurrency cap — and the headers tell you which one you're hitting, when to retry, and how much budget you have left.
Reading SSL certificate errors: the four most common ones, decoded
ERR_CERT_AUTHORITY_INVALID. NET::ERR_CERT_DATE_INVALID. ERR_CERT_COMMON_NAME_INVALID. ERR_SSL_VERSION_OR_CIPHER_MISMATCH. The browser tells you almost exactly what's wrong if you know how to read it. Here is what each one means, why it happens, and what to do.
The 5xx family: 500 / 502 / 503 / 504 / 520 and what each one is actually telling you
Every 5xx code is a server's way of saying 'something went wrong on our end.' But they are not interchangeable. 502 means upstream; 504 means upstream-but-slow; 503 means deliberately unavailable; 520 means Cloudflare-doesn't-know. Knowing which one you got cuts the bug-hunt by more than half.
Reading an HTTP redirect chain — the underrated debugging skill
When 'is the site down' turns out to be 'the site is fine, but the redirect chain is sending users somewhere unexpected,' the only useful diagnostic is the full hop-by-hop trail. Here's what each step tells you, and the patterns that crop up most often.
What HTTP 403, 404, 429, 500, 502, and 503 errors actually mean
Six HTTP status codes do most of the diagnostic work on a broken-website page. The class digit tells you whose fault it is; the second and third digits tell you which part broke. Here's what each one is really saying — and what to do about it.