How does 192,168,1,2,7,138 convert to port 1930 on IP address 192.168.1.2
How do i deduce the port and ip from a number that FTP throws? For example 192,168,1,2,7,138 converts to 1930 on IP address 192.168.1.2?
What is the logic behind?
The first four numbers indicate client IP, the second two numbers indicate the client port number. It's a hex to dec conversion.
16^2 * 7 + 138 = 1930
The first number stands for 3-rd and 4-th bit of a hex number (port number), the second is for 1-st and 2-nd bit of a hex number. So we have
7 = 07 in hex
138 = 8A in hex
Altogether we have
078A in hex which is 1930
or you can just skip that and convert only the first number to dec which is for 3-d and 4-th bit because of that "shift". The second number is already converted.