FTP server application data format for the data connection

The FTP server establishes a data connection just before a file transfer occurs. The connection is closed when the file transfer is complete. Table 1 shows the format of the application data set by the server for its data connection.

Table 1. FTP server application data for the data connection
Bytes	Description
1 - 8	The component ID of FTP, EZAFTP0S
9	Blank
10	The FTP connection: D Data connection
11	Blank
12 - 20	The user name of the FTP client, padded to the right with blanks. This field might be blank if the user is not logged into the FTP server.
21	Blank
22	Security protection for the connection: C Clear P Private S Safe
23	The security method used for the FTP connection if security protection is either Private or Safe; Blank otherwise. T TLS managed by AT-TLS G GSSAPI F TLS managed by FTP
24, 25	The security level if security method is TLS and the handshake has completed; blank otherwise (see Note): S2 SSLv2 S3 SSLv3 T1 TLSv1 11 TLSv1.1 12 TLSv1.2
26, 27	The security cipher used if the security method is TLS or AT-TLS and the handshake has completed; blank otherwise (see Note). If the value is 4X, the security cipher must be obtained from offset 33.
28	Blank
29	Data connection type: P Active (PORT) X Passive (EPSV) F Passive (PASV) T Active (EPRT) N Active, no command (this is the default)
30	Data transfer direction: S Inbound data transfer to this node R Outbound data transfer from this node
31	File type: D Directory as the result of a LIST or NLST command J JES file Q SQL uery function S Sequential or partitioned data set
32	File location: P PDS or PDSE data set S MVS™ but not a PDS or PSDE H UNIX file - *DEV.NULL (null directory)
33 - 36	The security cipher that is used if the security method is TLS that is managed by FTP or AT-TLS; blank otherwise (see Note).
37 - 40	Reserved blank
Note: This value is negotiated during the TLS handshake. Another TLS handshake can occur at any time. When the FTP server next updates the APPLDATA, this value might change.