Glossary · Networking
Port
A numbered channel on an IP address that directs traffic to a specific service, such as the port your proxy listens on.
If an IP address is a building, a port is a numbered door. A single address exposes thousands of ports, and each one can run a different service, which is how one machine serves web traffic on one port while accepting proxy connections on another. You connect to a proxy as an address-and-port pair for exactly this reason.
Ports carry conventions rather than rules. Web traffic gravitates to 80 and 443, but a proxy can listen wherever it is configured to, and providers routinely run different services, HTTP versus SOCKS, or different pools, on different ports of the same host.
This matters in practice because some networks only permit outbound traffic on a handful of expected ports. A proxy reachable only on an unusual port can be quietly unreachable from a restrictive network, even though the address itself is fine.
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