# PROXY PROTOCOL PREFIXES The proxy string may be specified with a `protocol://` prefix to specify alternative proxy protocols. (Added in 7.21.7) If no protocol is specified in the proxy string or if the string does not match a supported one, the proxy is treated as an HTTP proxy. The supported proxy protocol prefixes are as follows: ## `http://` Makes it use it as an HTTP proxy. The default if no scheme prefix is used. ## `https://` Makes it treated as an **HTTPS** proxy. ## `socks4://` Makes it the equivalent of --socks4 ## `socks4a://` Makes it the equivalent of --socks4a ## `socks5://` Makes it the equivalent of --socks5 ## `socks5h://` Makes it the equivalent of --socks5-hostname