PORT (Data Port)

 

The PORT i5/OS® FTP server subcommand identifies the data port on which the client will listen for a connection.

 

FTP server subcommand

PORT h1,h2,h3,h4,p1,p2

h n

Represents the system IP address and is a character string that is a decimal value between 0 and 255.

p n

Represents the TCP port number and is a character string that is a decimal value between 0 and 255.

To convert the p1 and p2 values to a TCP port number, use this formula: 

    port = ( p1 * 256 ) + p2

For example, in this PORT subcommand: 

   PORT 9,180,128,180,4,8

the port number is 1032 and the IP address is 9.180.128.180.

After it closes the connection, the FTP server cannot connect to the same client IP address and port number until a two-minute time delay has occurred as specified in TCP/IP Request for Comments (RFC) 1122. The FTP server can make a connection to the same client IP address on a different port number without this restriction.

Related reference
File Transfer Protocol server syntax conventions