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	protocol											FTP
		description															FTP - Protocol description.
		rfc										rfc959
		protocol										TCP					TCP - Protocol description.
			abbreviation									TCP					Transmission Control Protocol
			section									Header Format
				document								RFC-793					Section 3.1
				ascii								Header Layout					0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Acknowledgment Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Data | |U|A|P|R|S|F| | | Offset| Reserved |R|C|S|S|Y|I| Window | | | |G|K|H|T|N|N| | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Checksum | Urgent Pointer | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Options | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
				bits16								Source Port					The source port number.
				bits16								Destination Port					The destination port number.
				bits32								Sequence Number					The sequence number of the first data octet in this segment (except when SYN is present). If SYN is present the sequence number is the initial sequence number (ISN) and the first data octet is ISN+1.
				bits32								Ack Number					If the ACK control bit is set this field contains the value of the next sequence number the sender of the segment is expecting to receive. Once a connection is established this is always sent.
				bits4								Data Offset					The number of 32 bit words in the TCP Header. This indicates where the data begins. The TCP header (even one including options) is an integral number of 32 bits long.
				bits6								Reserved					Reserved for future use. Must be zero.
				section								Control Bits					6 bits (from left to right)
				bits16								Window					The number of data octets beginning with the one indicated in the acknowledgment field which the sender of this segment is willing to accept.
				bits16								Checksum					The checksum field is the 16 bit one's complement of the one's complement sum of all 16 bit words in the header and text.
				bits16								Urgent Pointer					This field communicates the current value of the urgent pointer as a positive offset from the sequence number in this segment. The urgent pointer points to the sequence number of the octet following the urgent data. This field is only be interpreted in segments with the URG control bit set.
				bits24								Options					Variable length. Options may occupy space at the end of the TCP header and are a multiple of 8 bits in length. All options are included in the checksum. See spec.
				bits8								Padding					Variable Length. The TCP header padding is used to ensure that the TCP header ends and data begins on a 32 bit boundary. The padding is composed of zeros.
			section									Messages					Messages used for the msg flow
				message								ACK					Acknowledgment
				message								SYN					Synchronize sequence numbers
				message								SYN+ACK					An accepted synchronization or connetion.
				message								DATA					Used to denote data being transmittednothing (no ack).
				message								DATA+ACK					Used to denote data with implicit ack.
				message								RST					Reset the connection
				message								FIN					No more data from sender
				message								FIN+ACK					The FINished msg to tell the connection is being closed.
		abbreviation										FTP					File Transfer Protocol
		section										req supported					The supported request by the FTP daemon
			message									ABOR					abort previous command
			message									ACCT					specify account (ignored)
			message									ADAT					send an authentication protocol message
			message									ALLO					allocate storage (vacuously)
			message									APPE					append to a file
			message									AUTH					specify an authentication protocol to be performed
			message									CCC					set the command channel protection mode to 'Clear' (no protection). Only available if the -c command-line option was given.
			message									CDUP					change to parent of current working directory
			message									CWD					change working directory
			message									DELE					delete a file
			message									ENC					send a privacy and integrity protected command (given in argument)
			message									HELP					give help information
			message									LIST					give list files in a directory (''ls -lgA'')
			message									MIC					send an integrity protected command (given in argument)
			message									MKD					make a directory
			message									MDTM					show last modification time of file
			message									MODE					specify data transfer mode
			message									NLST					give name list of files in directory
			message									NOOP					do nothing
			message									PASS					specify password
			message									PASV					prepare for server-to-server transfer
			message									PBSZ					specify a protection buffer size
			message									PORT					specify data connection port
			message									PROT					specify a protection level under which to protect data transfers
			message									PWD					print the current working directory
			message									QUIT					terminate session
			message									REST					restart incomplete transfer
			message									RETR					retrieve a file
			message									RMD					remove a directory
			message									RNFR					specify rename-from file name
			message									RNTO					specify rename-to file name
			message									SITE					non-standard commands (see next section)
			message									SIZE					return size of file
			message									STAT					return status of server
			message									STOR					store a file
			message									STOU					store a file with a unique name
			message									STRU					specify data transfer structure
			message									SYST					show operating system type of server system
			message									TYPE					specify data transfer type
			message									USER					specify user name
		section										deprecated					Deprecated requests
			message									XCUP					change to parent of current working directory (deprecated)
			message									XCWD					change working directory (deprecated)
			message									XMKD					make a directory (deprecated)
			message									XPWD					print the current working directory (deprecated)
			message									XRMD					remove a directory (deprecated)
		section										site req					request supported by SITE request
			message									UMASK					change umask. E.g., SITE UMASK 002
			message									IDLE					set idle-timer. E.g., SITE IDLE 60
			message									CHMOD					change mode of a file. E.g., SITE CHMOD 755 filename
			message									HELP					give help information. E.g., SITE HELP
		protocol										SFTP					SFTP - Protocol description.
			abbreviation									SFTP					Secure File Transfer Protocol