VPN and proxy glossary

These terms describe the two main ways to route traffic away from your device so third parties never see your real address.

Proxy server

An intermediary server that receives your request, forwards it to the destination, and returns the response. To the destination the traffic looks like it came from the proxy, not from you, which is how a proxy helps hide your origin IP. See the s4m proxy product for authenticated endpoints.

Forward proxy

A proxy that sits in front of clients and represents them to the wider internet — the everyday meaning of "proxy". It contrasts with a reverse proxy, which sits in front of servers. The s4m SOCKS5 and HTTP proxies are forward proxies.

SOCKS5

A low-level proxy protocol that relays raw TCP (and UDP) traffic for any application, not just web browsers. It supports authentication and does not alter your data. Point a client at proxy.s4m.online:1080 with USER:PASS to use it.

HTTP(S) proxy

A proxy that understands the HTTP protocol and is typically used for web traffic. For HTTPS it tunnels the encrypted connection with the CONNECT method without reading its contents. The s4m HTTP proxy listens on proxy.s4m.online:3128.

VPN

A Virtual Private Network encrypts all traffic leaving your device and routes it through a remote server, so every app is covered at once — unlike a proxy, which is usually configured per app. Explore the s4m VPN for a flat monthly rate (not metered per-GB) on paid plans.

WireGuard

A modern VPN protocol built around a small, auditable codebase and fast, up-to-date cryptography. It connects quickly and roams well between networks, and it is the default protocol on the s4m VPN.

OpenVPN

A mature, widely supported VPN protocol that runs over TLS. It is highly configurable and can be more firewall-friendly on restrictive networks, at the cost of more overhead than WireGuard. s4m offers OpenVPN as an alternative.

Once traffic leaves through a proxy or VPN, these terms describe the address it appears to come from and how much a connection reveals about you.

No-logs

A design goal where the provider does not record which sites you visit or keep connection metadata that could tie activity back to you. s4m is no-logs by design with a RAM-first architecture, so operational state lives in memory rather than on disk.

Datacenter proxy

A proxy whose IP is hosted in a data center. These are stable and cost-effective, though networks can recognise the ranges as non-residential. All of the paid s4m proxies are authenticated datacenter SOCKS5 and HTTP proxies.

Residential proxy

A proxy that routes through IP addresses ISPs assign to home users, so traffic appears to come from an ordinary household. s4m does not sell residential proxies — our paid proxies are datacenter, and residential IPs would require a different kind of provider.

Dedicated / personal IP

A static IP reserved for you alone rather than shared with other users. It gives you a stable reputation for whitelisting and stays associated with your s4m account. As an s4m add-on it binds to either your VPN or your proxy — see pricing.

Anonymity levels (transparent / anonymous / elite)

A grading of how much a proxy reveals. Transparent proxies pass your real IP along in headers (no privacy). Anonymous proxies hide your IP but signal that a proxy is in use. Elite (high-anonymity) proxies hide your IP and do not advertise themselves. Filter the free proxy list by level.

DNS leak

When your DNS lookups bypass the tunnel and reach your ISP's resolver, exposing the domains you visit even though the rest of your traffic is proxied or encrypted. A correctly configured VPN routes DNS through the tunnel; you can confirm with any DNS-leak test.

Exit node / exit IP

The last hop before the public internet, and the IP address the destination actually sees. With s4m that is the shared datacenter proxy IP, your VPN server, or — if you add one — your dedicated IP. Your real origin IP stays hidden behind it.

Speed and reliability matter as much as privacy, especially for automation. These terms cover both, plus how access is limited.

Latency

The round-trip delay between your device and the destination, usually measured in milliseconds. Every extra hop — including a proxy or VPN server — adds some latency, so choosing an endpoint geographically close to your target keeps it low.

Uptime

The proportion of time a service stays available and reachable. It matters most for proxies used in automation, where a dead endpoint breaks jobs. The free public list shows recorded check results. The catalogue retains historical records, including entries marked as not working. A recorded success does not guarantee a connection now. Review the status and timestamp, then validate an endpoint before use.

IP whitelisting

Restricting a service so only approved IP addresses can connect. A dedicated IP makes this practical: you whitelist one stable address instead of a rotating pool, which is why teams often pair whitelisting with a personal IP.

Usage throttling

Deliberately capping transfer speed or volume. On s4m, admins can tune usage limits on three axes — per account-type, per IP and per account — while paid VPN plans offer a flat monthly rate (not metered per-GB).