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Port 22 is the default port for SSH, which provides encrypted remote administration of Linux servers. Here you’ll find key details about the port and firewall commands to allow access to it selectively.
Built by Justin Schuessler
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Remote access · Well-known port · OSI layer 7
Encrypted remote access to the command line, plus file transfers via SFTP and SCP.
IANA: officially registered as ssh
Firewall commands
Open port
sudo ufw allow 22/tcpFor Ubuntu and Debian. ufw creates the rule for both IPv4 and IPv6. If ufw is disabled, allow SSH first (sudo ufw allow 22/tcp), then enable it with sudo ufw enable, or you'll lock yourself out.
On a ZAP-Hosting VPS with an active network firewall, you also need to allow the port in the Customer Panel.
Port 22 explained
Port 22 lets you connect to your VPS or dedicated server’s command line via SSH. The entire connection is encrypted, including the login. SFTP and SCP file transfers and Git access over SSH use the same port. You can also create SSH tunnels to access other services securely without opening their ports.
SSH was developed in 1995 by Tatu Ylönen at Helsinki University of Technology as a secure replacement for Telnet, rlogin and rsh. The version used today, SSH-2, is standardized in RFC 4251 through RFC 4254. The IANA lists port 22 under the name “ssh” as a well-known port. OpenSSH is the most widely used implementation.
Port 22 is scanned around the clock for weak passwords. Use SSH keys and disable password login with PasswordAuthentication no in sshd_config. Allow root login only with a key, or disable it entirely. A tool like fail2ban automatically blocks IPs after multiple failed attempts. If you have a static IP, allow access to port 22 only from that IP. Moving SSH to another port only reduces log noise; key-based login is what actually improves security.
More ports
These ports are often part of the same setup. Click one to see its explanation and firewall commands.
View all well-known ports and the complete IANA list
Port list source: IANA Service Name and Transport Protocol Port Number Registry, as of October 22, 2026. iana.org
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FAQ
Quick answers about port 22.
With ufw, use sudo ufw allow from 203.0.113.10 to any port 22 proto tcp and replace the example IP with your own. Then delete any existing general rule for port 22. Always keep an existing SSH session open while making the change so you do not lock yourself out.
SSH uses TCP. For the firewall, sudo ufw allow 22/tcp or sudo firewall-cmd --permanent --add-port=22/tcp is enough.
Using a different port reduces automated login attempts in your logs but does not protect against targeted attacks. SSH keys, disabled password login, and fail2ban matter more. If you change the port, allow the new port through the firewall before restarting sshd.
Both provide access to a remote command line. Telnet sends everything in plain text, including the password, while SSH encrypts the entire connection. You should therefore use only SSH for servers.
Any more questions?
Contact SupportWith a ZAP-Hosting VPS, you have root access, can set up services and firewall rules yourself, and can immediately see which ports are open.
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