Requests and responses.
WHAT HAPPENS WHEN A PAGE LOADS
The name is resolved A connection is opened, usually encrypted A request is sent The server responds
Additional resources are requested: images, styles, scripts
WHY THAT LAST POINT MATTERS
A single page involves many requests, each costing time.
WHAT A STATUS CODE INDICATES
Success Redirection A problem with the request A problem on the server
WHY THAT DISTINCTION MATTERS IN SUPPORT
It says which side to investigate.
WHAT THE COMMON ONES MEAN
- Not found: the resource does not exist at that address
- Forbidden: it exists, access is denied
- Server error: the server failed processing the request
- Service unavailable: the server is reachable but cannot serve
WHAT ENCRYPTION PROVIDES
Protection of the connection, and verification of the certificate's name.
WHAT IT DOES NOT PROVIDE
Assurance that the site is honest.
WHAT TO CHECK FOR A CERTIFICATE WARNING
Expiry Whether the name matches The device clock
THAT LAST ONE
Checked last by most people, and frequently the cause.
