GLOSSARY
SOCKS5
SOCKS5 is a proxy protocol, specified in RFC 1928, that relays network connections at a lower level than HTTP. It can carry almost any kind of traffic, including web, email, chat and game connections, and it supports username and password login. It also supports UDP.
Why it matters
Because it does not interpret the traffic, a SOCKS5 proxy does not add HTTP headers that reveal it, and it works with many applications. It does not encrypt anything by itself. Another point to check is where the name lookup happens: with some settings your device resolves the website name locally, which can leak lookups, while remote DNS settings send the name to the proxy.
In practice
Applications that support SOCKS5 let you enter a host and port, with 1080 as a traditional port. Some support a variant called SOCKS5h, where the proxy resolves names. Browsers like Firefox have a setting to send DNS through a SOCKS5 proxy. Use the proxy checker to test whether the exit address and country match what you expect.
Related terms
- Proxy: A proxy server is an intermediary that makes requests on your behalf.
- HTTP proxy: An HTTP proxy is a proxy that understands web requests.
- DNS leak: A DNS leak is when your device sends its DNS lookups to a resolver you did not intend, usually your internet provider's, while you believe a VPN or proxy is handling your traffic.
- Port: A port is a number from 0 to 65535 that tells a computer which program should receive incoming network data.