What is Port 443 and why it’s needed for secure web browsing

A variety of complex systems and strategies work together to improve digital communication. While users are often familiar with firewalls and multi-factor authentication, ports are just as critical. These humble pathways are the true workhorses of modern internet security, and one port in particular plays a critical role: port 443.

As the standard port for HTTPS, port 443 allows for encrypted web communications and helps protect users from digital risks such as data breaches, man-in-the-middle attacks, and other threats when used with SSL/TLS certificates.

Working alongside SSL/TLS certificates, port 443 promotes the safe and secure transfer of data between browsers and servers. These certificates authenticate identities and establish trusted connections, while port 443 provides the necessary channel for this encrypted communication.

Security-focused elements such as port 443, HTTPS, and SSL certificates are closely linked, but they can seem complex due to their highly technical nature. To clarify these essentials, we will discuss the role of port 443 in promoting secure communication and explain what it means when issuing and deploying SSL certificates.

What is Port 443?

Open ports establish connections between devices, functioning as endpoints while ensuring that network traffic reaches the intended destination. These ports are always numbered, and depending on the number, they serve different purposes in digital communication.

Port 443 is the default TCP port for HTTPS traffic and is one of the most well-known ports, functioning as a gateway that allows data to reach its desired destinations both successfully and securely. This is the standard port for Hypertext Transfer Protocol Secure (HTTPS), a more secure version of HTTP, which is responsible for encrypting data exchanged between users and web servers. HTTPS uses SSL/TLS over port 443 to encrypt communication between browsers and servers. These protocols play a vital role in protecting data in transit. This port is closely tied to the rise of HTTPS and the use of Secure Sockets Layer (SSL) / Transport Layer Security (TLS) certificates for encryption purposes. (While often referred to as SSL, modern HTTPS encryption relies on the more secure TLS protocol, which has replaced SSL.)

Since it was introduced, port 443 has seen widespread adoption across many sectors and is especially valued when sensitive information needs to be shared. This is a top strategy for banking and in eCommerce but also proves beneficial in far-reaching industries such as healthcare and even hospitality.

HTTPS vs Port 443 – understanding the difference

HTTPS and Port 443 are closely connected and share similar priorities, but they are not one and the same. After all, as its full name (Hypertext Transfer Protocol Secure) suggests, HTTPS is a protocol. This means that it maintains strict standards for securely transmitting data, complete with the use of encryption.

Port 443 functions as the channel through which this data must pass in order to reach its final destination. This port can be thought of as a tunnel or entryway, while HTTPS is more akin to the map or blueprint that helps data reach its intended destination. Both are important, making sure that physical endpoints are available along with the rules and procedures that help data reach desired endpoints without being compromised.

How HTTPS and SSL/TLS work over Port 443

SSL/TLS certificates are digital documents designed to verify identities and establish encrypted communications. These certificates make it possible to use HTTPS. From there, port 443 provides a channel through which this encrypted data can flow. These digital certificates involve a few main priorities: encryption to preserve confidentiality, authentication to verify server identities, and integrity to ensure that data remains unchanged as it moves from the sender to the intended recipient.

Critical to this process is the TLShandshake, which involves a complex series of steps designed to establish a secure connection. This may be initiated by the client in the effort to reach a particular HTTPS URL. At this point, the web browser initiates a secure connection via port 443, sending a Transmission Control Protocol (TCP) request.

Next, the SSL/TLS certificate is sent to the client. This includes information about the public key and allows the client to verify the server's identity, typically by using trusted Certificate Authorities (CAs). Next up: a secure key exchange process, which facilitates the safe encryption and decryption of sensitive information. Following a successful handshake process, all subsequent data will be encrypted so that both parties can communicate with confidence.

Why Port 443 is considered secure

Port 443's reputation for security largely relates to its status as the default port for HTTPS. It has been purposefully designed to support HTTPS and to allow SSL certificates to serve their primary functions of encryption and authentication. Port 443 is also uniquely equipped to promote compliance with data-in-transit encryption requirements, allowing for secure online transactions. This is important in the context of PCI DSS (Payment Card Industry Data Security Standard), which involves strict mandates for encrypting credit card data.

In the healthcare sector, port 443 helps organizations maintain full compliance with HIPAA, making it possible to meet a long list of requirements for safeguarding PHI (Protected Health Information). HIPAA's Security Rule mandates that all electronically transmitted PHI be fully encrypted.

Comparing to other ports (80 and 53)

Port 443 shares much in common with other ports including an overarching emphasis on communication between devices and over a network. These ports may act as endpoints, but they differ in how they handle various types of data traffic, and, more importantly, how (or whether) they secure that data through encryption.

• Port 80: Centered around unencrypted HTTP traffic, port 80 was introduced during the early years of the internet and, for quite some time, functioned as a default option for accessing websites via HTTP. This port still offers some advantages, such as the ability to quickly share non-sensitive information, not to mention, backward compatibility and even opportunities for delivering cached content. These days, however, port 443 is generally the preferable option from a security perspective.

• Port 53: Focused on Domain Name System (DNS) queries, port 53 is a versatile option that supports both User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) for various types of queries. This can be useful for managing large networks, with load balancing often coming into play. Both ports serve valuable roles within the modern digital ecosystem, but they have distinct purposes: port 443 is all about promoting secure data transmission between websites and users, while port 53 facilitates that transition from domain names into IP addresses.

Although DNS typically uses port 53, DNS over HTTPS (DoH) sends DNS queries over port 443 using HTTPS to provide encryption. DoH relies on port 443 to keep traffic hidden and could even limit the potential for third-party tampering.

Use of Port 443 in VPNs and restricted networks

Virtual Private Networks (VPNs) can make the most of SSL/TLS protocols to achieve encrypted connections and to facilitate a more secure approach to maintaining remote access. Users can take confidence in knowing that these pathways are secure, making this an ideal setup for corporate entities that maintain a sizable remote or hybrid workforce.

Port 443 has a major role to play in establishing these secure connections, often acting as the default port for HTTPS traffic. As a result, VPNs can operate seamlessly over port 443, especially in restricted networks where standard VPN ports may be blocked. Other advantages include the ability to connect from a wide range of networks, along with simplified configurations that may reduce burdens on IT teams.

Why HTTPS Port 443 remains critical for modern web security and how Sectigo can help

Port 443, HTTPS connections, and SSL certificates all have important roles to play in promoting secure digital communication. While the underlying technologies may be complex, they collectively play a vital role in keeping sensitive data private and protected during digital exchanges. Sectigo, a trusted Certificate Authority, can aid in this by providing the SSL/TLS certificates needed to encrypt and authenticate critical data exchanged.

Offering a wide range of SSL/TLS certificates (along with automated lifecycle management to streamline certificate issuance and keep up with upcoming shorter certificate timelines), Sectigo can simplify the process of securing websites. The result? A trusted pathway to digital peace of mind.

Learn more about our digital certificates, our robust integrations, and our other opportunities for securing your digital infrastructure. Check out our SSL certificate offerings and take the next step towards achieving a fully secure and compliant online presence.

Related posts:

How SSL certificates can help prevent Man-in-the-Middle attacks

What is an SSL certificate & how does it work

Certificate Authorities: What they are & why they’re important