Unit 1 · How the web works
Why a 404 doesn’t mean the internet is down
A 404 is a reply from a server: it looked for the address you asked for and found nothing. Your internet worked fine to get that reply. With no connection you get no status code at all.
The mix-up
What people often think
“404 means the internet is down.”
What the tutor says
A 404 came from the server, so your internet worked fine to reach it. With no internet you get no status code at all.
If your internet were off, who would have sent the 404?
How it works
Every status code is part of a response, and a response has to travel back across the internet to reach you. So a 404, or a 500, proves the connection is working. When the internet really is down, the browser shows its own error, such as “no internet” or “server not found”, because nothing answered.
A 404 usually means a typo in the address, a deleted page or a broken link. The fix belongs to whoever owns the link: correct the address, restore the page, or redirect the old address to the new one.
Close cousins of this mix-up
The tutor watches for these in the same lesson.
“Error pages mean the internet is down.”
The visitors received a response, so their internet works. The server sent that 500.
Practise it with a tutor watching
Status codes
Read a status code and say who needs to fix the problem.
Free, no account needed.