`socks': Connect through a socks server;
`tls': Connect with TLS;
`ssl': Connect with SSL (deprecated, use `tls' instead);
-`native': Connect directy."
+`native': Connect directly."
:type '(radio (const :tag "Telnet to gateway host" :value telnet)
(const :tag "Rlogin to gateway host" :value rlogin)
(const :tag "Use SOCKS proxy" :value socks)