Passive FTP Question

in Genius Bar edited January 2014
When clients connect to my OS X (Tiger) FTP server they see entries in their client logs similar to the line below:

227 Entering Passive Mode (65,155,41,36,201,186). is my server's public IP. But what are the other numbers (the 201 and the 186)? The last 2 numbers change all the time (even during a single session), and I assumed they were the passive port numbers being used for a particular transfer at first. Then after studying the number I have concluded that they are not the passive port numbers - I am positive of this now. I reserved poers 51000 to 51999 for Passive mode on both my server and my router.

Anyone know what those numbers mean?


  • Reply 1 of 1
    endymionendymion Posts: 375member
    From this link


    The first four octets are the IP address while the last two octets comprise the port that will be used for the data connection. To find the actual port multiply the fifth octet by 256 and then add the sixth octet to the total. Thus in the example below the port number is ( (14*256) + 178 ), or 3762.


Sign In or Register to comment.