Proxy port

A proxy port is the number you connect to alongside the proxy's host address — the 8080 in 1.2.3.4:8080 — and it tells the proxy server which of its services should handle your connection. One machine can listen on many ports at once, each doing something different.

Why it matters when you buy proxies

The port is how a provider separates the endpoints it offers you. HTTP/HTTPS and SOCKS5 are different protocols, so they get different ports on the same host — that is why your credentials page lists more than one number, and why the two are not interchangeable.

Get it wrong and the failure is unhelpful. Pointing a SOCKS5 client at an HTTP port does not return an authentication error; you get a timeout, a connection reset, or a garbled response, and it looks like the proxy is down. Before assuming a dead proxy, confirm the port matches the protocol your tool is speaking.

A concrete example

Your dashboard hands you a host, a port, a username and a password for each endpoint. In a browser's proxy settings you pick the type — HTTP or SOCKS5 — and enter the matching port for that type. In a command-line tool the whole thing usually collapses into one string shaped like protocol://username:password@host:port, where the protocol at the front and the port at the end have to agree with each other. The username and password half of that string is covered under proxy authentication.

One last thing worth ruling out: restrictive office and hotel networks sometimes allow only common ports outbound, so a proxy on an unusual port can fail from one location and work perfectly from another. Test from a network you control before deciding the proxy itself is at fault.