AdiIRC

Added in 2.4

/proxy [-cmNgNs[+|-]d] [on|off] [server] [port] [username] [password]

Change global or current server proxy settings.

Switches

-c - Clears the username and password fields.
-mN - Sets the connection type, if N = 4 or 5 for Socks4 or Socks5, or p for http proxy.
-gN - Enables or disables global proxy settings for current server, if N = 0 Disable, if N = 1 Enable. (AdiIRC only)
-s - Change settings for current server instead of global. (AdiIRC only)
+|-d - Turns dcc through proxy on or off.

Parameter

[on|off] - Enables or disables proxy.
[server] - Proxy server to connect to.
[port] - Proxy port to connect to.
[username] - Proxy username.
[password] - Proxy password.