Have you ever heard of an internet provider caching pages?
As a matter of fact I have, but it was back in 2006 and we were still on dial-up. Ten years later I am more likely to come across one of the following:
- PHP code caching, such as OPcode. This accounts for 90% of "weird" issues we've seen with our clients.
- Broken PHP installations. For example, I've seen some versions of PHP 5.5 having a miscompiled cURL module which returns a-ok for PUT requests even though it transfers no data (whaaaaaaat?!)
- Hosting providers putting a page cache –such as Varnish– in front of a site. Goodbye sanity, hello weird page refresh issues.
- Same as above with a CDN. Bonus BDSM points if they have CDN in front of Varnish in front of NginX configured as reverse proxy in front of Apache (I've had the misfortune of debugging such a monstrosity).
- BONUS ROUND! Transparent caching proxies installed by the IT department without telling the web site management team.
The next time this happens I will try a different machine first then if the problem persists, I will try another internet provider.
If you have a mobile data (3G/4G/LTE) connection that supports tethering try using that, ideally with another machine. That's a fast way to see if the problem is on the network or the server.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
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