SOCKS protocol incluing sock4 and sock5. It is the rfc standard of the proxy.
Communication
SOCK4 only supports TCP, 1080 is the default port. The server can also set other ports.
SOCK5 supports both TCP and UDP, 1080 is the default port.
How to block SOCKS?
Because SOCKS does not use a fixed port, so you can not block them only by
disable the ports in the firewall. The only way is using professional tools to block SOCKS.