Browsers & Accounts · HTTPS & Certificates · Lesson 4 of 5

HTTPS-Only and Secure DNS

Two browser settings that keep more of your browsing scrambled.

HTTPS-only mode

A page that uses plain HTTP, without the S, isn't scrambled. Anyone on the same network could read it, or quietly change it on its way to you.

Most sites use HTTPS now. Many browsers also try the HTTPS version of a page first, on their own.

An HTTPS-only mode goes one step further. The browser tries HTTPS for every page. If a page can't use it, the browser warns you before opening it.

Where to find it:

• Chrome: Settings, then Privacy and security, then Security. Turn on Always use secure connections.
• Firefox: Settings, then Privacy & Security. Look for HTTPS-Only Mode.
• Edge and Safari switch many sites to HTTPS automatically. Check the security part of their settings for extra options.

What it protects:

• Pages can't be read or changed by others on the same Wi-Fi.
• A trickster can't quietly push you onto an unscrambled copy of a site.

What it doesn't protect:

• Fake sites. A look-alike domain can still have HTTPS.
• Harmful downloads, or a computer that already has malware.

When the warning appears, read it calmly. A plain page is fine for reading a menu or a bus timetable. Don't type a password, card number or anything private into it.

One common case: hotel and cafe Wi-Fi sign-in pages. Some are plain HTTP, so you may see the warning there. That's expected. It's fine to enter what the network asks for, like a room number. Never type a bank password or card number on a Wi-Fi sign-in page.

Secure DNS in plain words

In Mobile Networking, you learned that DNS is the internet's phone book. It turns a name like bank.example into the number address computers use.

Every time you visit a site, your computer asks a DNS server for that number. This is called a lookup.

With plain DNS, lookups travel unscrambled. So the Wi-Fi owner, or someone else on the network, can see which sites you look up. On a bad network, someone could even change the answer and send you somewhere fake.

Secure DNS, also called DNS over HTTPS, sends those lookups scrambled, the same way HTTPS scrambles web pages.

Where to find it:

• Chrome: Settings, then Privacy and security, then Security. Turn on Use secure DNS.
• Edge: Settings, then Privacy, search, and services. In the Security part, turn on Use secure DNS.
• Firefox: Settings, then Privacy & Security. Look for DNS over HTTPS.
• Safari uses your Mac's own network settings.

You can usually keep the default provider. You may also pick a well-known one from the list.

What it protects:

• Your lookups are hidden from others on the same network.
• It's harder to fake the answer and send you to the wrong place.

What it doesn't protect:

• The DNS provider you choose still sees your lookups.
• The network can often tell which site you visit in other ways.
• It doesn't stop look-alike domains or scam pages.

Think of it as one more layer, not an invisibility cloak. On a school or work computer, the people who run it may manage this setting for you.