This article explains what port 443 is used for and why it’s important.

What Are Ports For?

When you go on a website, your computer reaches out to the server hosting it. It looks for a connection on either the HTTP or HTTPS port, because they’re the ones associated with web traffic.

The server will make the connection to either port and send back the website information, which your computer will receive on the same port.

Ports not only ensure network connections make it to the right place, but they also make sure traffic doesn’t get mixed up.

Ports are also valuable for security reasons. You can control which ones are open and accessible, on either your computer or a server on the Internet. By blocking access to unused ports, either with a firewall or some other mechanism, you can minimize ways an attacker could access your computer.

What Is Port 443 Used For?

Have you ever seen the lock icon next to a URL in your browser’s address bar? Maybe you’ve even noticed https:// rather than http:// at the beginning of a URL. In both instances, you’ve connected to a website using the secure HTTPS protocol instead of HTTP.

HTTPS establishes an encrypted connection with a web server, rather than the unencrypted HTTP one. Since HTTP and HTTPS are two different protocols, they use two different ports. HTTP is available on port 80, and HTTPS is on port 443.

Whenever you connect to a website beginning with https:// or you see the lock icon, you’re connecting to that web server over port 443.

Why Port 443 Is Important

Port 443 is the standard port for all secured HTTP traffic, meaning it’s absolutely essential for most modern web activity. Encryption is necessary to protect information, as it makes its way between your computer and a web server.

That encryption prevents things like your passwords and sensitive information displayed on pages (like banking info) from being snooped on by anyone along the way. With regular HTTP over port 80, everything exchanged between your computer and a website is available for anyone to see in plain text.

Port 443 also enables websites to be available over both HTTP and HTTPS. Most websites are configured to work with HTTPS over port 443, but if it isn’t available for some reason, the website will still be live over HTTPS on port 80.

In the past, not every web browser supported HTTPS, meaning it wasn’t universally accessible. Now, though, most major browsers are moving to mark websites that don’t offer HTTPS traffic as insecure.

How to Use Port 443

When browsing the web, there usually isn’t anything the average person needs to do to connect over port 443. You can manually enter https:// before the URLs you visit, but that usually isn’t necessary.

If you want to ensure you’re using HTTPS whenever possible, look into the HTTPS Everywhere add-on from the Electronic Frontier Foundation(EFF). It’s available for browsers like Chrome, Firefox, and Opera.

Server administrators, however, need to take extra care to ensure their websites are available over port 443. You’ll need to configure your web server applications (such as Apache or Nginx) to serve your website on port 443; for the encryption to work, you’re going to need an encryption certificate.

You can purchase them from your web host or any number of certificate authorities. Let’s Encrypt is another excellent option for free SSL encryption certificates.