SSH (Secure Shell) is the most widely used protocol for adding security to remote connections. It encrypts all traffic between your device and a remote server, authenticates both sides of the connection, and prevents eavesdropping or tampering. But SSH isn’t the only option. Several protocols secure remote connections depending on the use case: TLS protects web and application traffic, VPN protocols like IPsec and WireGuard encrypt entire network tunnels, and newer Zero Trust frameworks are replacing traditional approaches altogether.
How SSH Secures Remote Connections
SSH was designed specifically to replace older, unencrypted remote access tools like Telnet and rlogin. It operates over TCP port 22 and is built from three layered components. The transport layer handles server authentication, encryption, and data integrity. A separate user authentication layer verifies the client’s identity. And the connection layer multiplexes everything into logical channels, so you can run multiple sessions over a single encrypted tunnel.
When you connect to a remote server via SSH, the server presents a host key so your client can verify it’s talking to the right machine. If you’ve connected before, your client checks this key against a stored fingerprint. This prevents an attacker from impersonating the server and intercepting your session. SSH also uses message authentication codes with incrementing sequence numbers on every packet, which blocks both data tampering and replay attacks.
One of SSH’s strongest security features is support for public key authentication instead of passwords. A password, no matter how complex, can be guessed or brute-forced. A cryptographic key pair is fundamentally different: the private key never leaves your machine, and possessing someone’s public key doesn’t let you decrypt anything. The private key also can’t be mathematically derived from the public key, making this method far more resistant to attack.
SSH-Based File Transfer: SFTP and SCP
SSH also serves as the foundation for secure file transfers. SFTP (SSH File Transfer Protocol) runs over an SSH session on port 22, wrapping every file operation in the same encryption used for shell access. SCP (Secure Copy) works similarly, transferring files over SSH without needing a separate protocol or port. Both are significant improvements over plain FTP, which sends credentials and data in cleartext.
FTPS takes a different approach, layering TLS encryption on top of traditional FTP. It typically runs on port 21 or 990 and requires managing TLS certificates separately. SFTP is generally simpler to configure and firewall-friendly since it uses a single port, while FTPS can require opening multiple ports for data connections.
TLS: Securing Web and Application Traffic
Transport Layer Security (TLS) is the protocol behind HTTPS and secures most web-based remote connections. When you log into a remote management console, access a cloud application, or connect to webmail, TLS is encrypting that traffic.
TLS 1.3, the current version, made substantial security improvements over TLS 1.2. Every TLS 1.3 session provides forward secrecy, meaning that even if an attacker later obtains the server’s private key, they can’t decrypt previously captured traffic. In TLS 1.2, forward secrecy was optional and often not configured. TLS 1.3 also removed support for older, weaker cipher suites and reduced the handshake to a single round trip, making connections both faster and more secure. According to NIST, TLS 1.2 will not be updated to support post-quantum cryptographic algorithms, giving organizations another reason to move to 1.3.
VPN Protocols for Full Network Encryption
When you need to secure not just a single connection but all traffic between two networks or a remote worker and an office, VPN protocols step in. The three most common are IPsec, OpenVPN, and WireGuard.
OpenVPN uses the OpenSSL library and SSL/TLS for its key exchange, supporting encryption up to 256-bit. A typical configuration uses AES-256 for encryption, a 2048-bit RSA handshake, and HMAC SHA-1 for authentication. It can run over either TCP or UDP, which makes it flexible for getting through restrictive firewalls.
WireGuard takes a leaner approach. Instead of offering a menu of cipher options, it uses a fixed set of modern cryptographic primitives: ChaCha20 for encryption, Poly1305 for authentication, Curve25519 for key exchange, and BLAKE2s for hashing. This simplicity means fewer configuration mistakes and a much smaller codebase to audit. WireGuard operates only over UDP, and its handshake is built on the Noise protocol framework. The result is noticeably faster connection setup compared to OpenVPN or IPsec.
Securing Remote Desktop Access
Remote Desktop Protocol (RDP) is the standard way to remotely control a Windows machine, running on TCP and UDP port 3389. RDP has its own security layers, and choosing the right one matters significantly.
At its most secure, RDP uses TLS encryption combined with Network Level Authentication (NLA). NLA requires users to authenticate before the remote session is even established, which prevents unauthorized users from reaching the login screen and reduces exposure to brute-force attacks. The “Negotiate” setting, which is the default, tries to use TLS first and falls back to RDP’s built-in (weaker) security layer if the client doesn’t support it. If you select the basic RDP Security Layer, NLA becomes unavailable entirely, leaving the connection more vulnerable.
Because RDP is a frequent target for attackers, many organizations tunnel it through a VPN or SSH connection rather than exposing port 3389 directly to the internet. Changing the default port provides only minimal obscurity, not real security.
Zero Trust: Beyond Perimeter Security
Traditional VPNs operate on a trust-the-network model. Once a remote user authenticates and enters the network perimeter, they often can access everything as if they were physically on-site. Zero Trust Network Access (ZTNA) flips this assumption. No user or device is inherently trusted, even after authentication.
ZTNA segments the network into small zones of control and grants least-privilege access based on role or need. Even if a user has permission to reach one application, that doesn’t grant access to anything else. Each request is verified independently. This approach limits the damage from compromised credentials because an attacker who gains access to one resource can’t move laterally across the network the way they could through a traditional VPN.
Choosing the Right Protocol
- Command-line server access: SSH is the standard. Use public key authentication and disable password login for the strongest protection.
- File transfers: SFTP is the simplest secure option, running over SSH on a single port.
- Remote desktop: RDP with TLS and NLA enabled, ideally tunneled through a VPN or SSH rather than exposed directly.
- Encrypting all traffic to a network: WireGuard for speed and simplicity, OpenVPN for flexibility and broad compatibility.
- Web applications and cloud services: TLS 1.3 secures these connections automatically in modern browsers.
- Enterprise environments with many remote users: ZTNA provides granular, per-application access control that traditional VPNs can’t match.
In practice, most secure remote setups combine several of these protocols. You might use SSH to manage servers, a WireGuard VPN for remote workers, TLS for web applications, and ZTNA policies layered on top. The right combination depends on what you’re connecting to, who needs access, and how much of the network you need to protect.