'Get IP Mask from IP Address and Mask Length in Python
Given an IP Address in dotted quad notation, for example:
192.192.45.1
And a mask length for example 8, 16, 24 typically, but could be anything i.e. 17.
Can somebody please provide the code in python to calculate the subnet mask? Preferably I could get the result as 32-bit integer so that it is easy to hash and then reinterpret as dotted quad when necessary for printing. I see that python has a socket library which is basically a wrapper around the unix socket api. I also saw it has the function inet_ntoa(), but it returns some sort of packet struct. I'm not terribly familiar with the Python struct library, so I was hoping some other would have some ideas. Thanks!
Solution 1:[1]
You can calcuate the 32 bit value of the mask like this
(1<<32) - (1<<32>>mask_length)
eg.
>>> import socket, struct
>>> mask_length = 24
>>> mask = (1<<32) - (1<<32>>mask_length)
>>> socket.inet_ntoa(struct.pack(">L", mask))
'255.255.255.0'
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | John La Rooy |