Learning hexadecimal conversion to decimal.

hexa = 6
decimal = 10

hexadecimal = 16


HEX  DEC
0     0
1     1
2     2
3     3
4     4
5     5
6     6
7     7
8     8
9     9
A    10
B    11
C    12
D    13
E    14
F    15

If you recall base 10 went something like this:

  10					10 				1
x 10                                   x 1                            (ones)
_____				      _____                           _______

100 for the hundreds column           10 for the tens column           1 for the ones column

So that the number 543 in Decimal translates to a 3 in the ones column, 
4 in the tens column and a 5 in the hundreds, and you have this:

00's |  tens  |  ones
______________________

100      10       1
x 5      x4      x3
___     ___     ____

500      40       3    and 500 + 40 + 3 = 543

So that in Hexadecimal the number table will look like this, instead of using base 10, hexadecimal
uses a base 16.

 16  |   16   |  ones
x16      x1
____   _____

256  |	 16   |   1

So a hexadecimal number of 2ED would work out like this:


256 column  |  16 column    | ones column
            |               |
    2       |     E         |       D
  x 256         E = 14		  D = 13
__________    (see above)       (see above)

                  16		     13
                x 14               x  1
               _______            ________
   512            224                13

512 + 224 + 13 = 749.  Thus hexadecimal number 2ED translates to decimal number 749

Port 749 is reserved for kerberos administration according to the well-known ports authorization:

http://www.iana.org/assignments/port-numbers

IANA is the governing factor behind the Internet. They are the rule makers.

Side note: Of course windows Calculator (Scientific view) will translate hexadecimal
octal and binary to decimal for you.