Domains, DNS & HTTPS

Three parts of opening a website, and what each one actually does.

A name, an address and a secure connection

A web address brings several separate systems together. The domain is the name you type. DNS helps find the server address associated with that name. HTTPS protects the connection between your browser and the server it reaches.

What DNS does

Computers connect using network addresses. A DNS resolver looks up records for a domain and returns the relevant information. A website can have more than one address, and different visitors may receive different answers.

Browsers, operating systems and resolvers can keep answers in a cache. This saves repeated lookups, but it also means a recent address change may take time to appear everywhere.

What HTTPS adds

HTTPS encrypts data in transit and lets the browser check that the certificate is valid for the requested name. It does not establish that every statement on a page is true, or that a business is trustworthy.

When a page will not open

Read the browser's exact error before changing settings. An unresolved name points toward a lookup problem. A certificate warning points toward a different set of checks, including the device clock and the name in the address bar.

Do not dismiss certificate warnings just to reach a page. Check the address and device time, and contact the site operator if the warning persists.