Fairbanks FB3000 Kernel Program Operators Manual - Manual (Page 62)

Appendix VII: SOCKS Information
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APPENDIX VII: SOCKS INFORMATION, CONTINUED
The SOCKS 5 Protocol, an extension of the SOCKS 4 Protocol that offers more
choices of authentication, is defined in RFC 1928.
The initial handshake now consists of the following:
Client connects and sends a greeting which includes a list of authentication methods
supported.
Server chooses one (or sends a failure response if none of the offered methods are
acceptable).
Several messages may now pass between the client and the server depending on
the authentication method chosen.
Client sends a connection request similar to SOCKS 4.
Server responds similar to SOCKS 4.
The authentication methods supported are numbered as follows:
0x00 - No authentication.
0x01 – GSSAPI.
0x02 - Username/Password.
0x03-0x7F - Methods assigned by IANA.
0x80-0xFE - Methods reserved for private use.
The initial greeting from the client is:
Field 1: SOCKS version number (must be 0x05 for this version).
Field 2: Number of authentication methods supported, 1 byte.
Field 3: Authentication methods, variable length, 1 byte per method supported.
The server's choice is communicated:
Field 1: SOCKS version, 1 byte (0x05 for this version).
Field 2: Chosen authentication method, 1 byte, or 0xFF if no acceptable methods
were offered.