What is a port?
A server has one address, called an IP address. But it runs many services at once. A port is a numbered door on that address. Each service waits at its own door. Think of an apartment block. The IP address is the street address. The port is the flat number.
The main web ports
| Port | Used for |
|---|---|
| 80 | HTTP. Normal web pages with no lock. |
| 443 | HTTPS. Web pages protected by SSL, the digital lock. |
| 8080 | Often used as a second HTTP port or for test sites and apps. |
| 8443 | Often used as a second HTTPS port. |
Browsers use port 80 for http:// and 443 for https:// without showing it. That is why you never type the number for normal sites.
Other ports you may meet
- 21: FTP, for uploading files.
- 22: SSH and SFTP, for safe remote access and safe file transfer.
- 25, 465, 587: sending email.
- 110, 995: POP3 email.
- 143, 993: IMAP email.
- 3306: MySQL databases.
- 2083: cPanel over HTTPS, on many hosts.
How to use a custom port
If a site runs on another port, add it after the address with a colon:
http://example.com:8080This opens the site on port 8080.
How to check which ports are open
This needs root access on a Linux VPS or dedicated server.
- Connect to your server with SSH.
- Type the command below and press Enter.
ss -tulpnThis lists the open ports and the program using each one.
Warning: Do not close port 22 or the port you use to reach the server, or you may lock yourself out. Do not open ports you do not need. Each open port is one more door for attackers.
If a port is blocked
A firewall can block ports. A firewall is a guard that decides which traffic may enter. If your site does not open, ask Hostvento support to check the firewall. You can open a support ticket.
Quick recap
- A port is a numbered door on a server.
- Web uses 80 for HTTP and 443 for HTTPS.
- Add
:8080style numbers to the address for custom ports. - Use
ss -tulpnto see open ports. - Keep only the ports you need open.