networking - How can I check if an ip is in a network in Python?

Question

Given an ip address (say 192.168.0.1), how do I check if it's in a network (say 192.168.0.0/24) in Python?

Are there general tools in Python for ip address manipulation? Stuff like host lookups, ip adddress to int, network address with netmask to int and so on? Hopefully in the standard Python library for 2.5.

Answer 1

Using ipaddress (in the stdlib since 3.3, at PyPi for 2.6/2.7):

>>> import ipaddress
>>> ipaddress.ip_address('192.168.0.1') in ipaddress.ip_network('192.168.0.0/24')
True

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If you want to evaluate a lot of IP addresses this way, you'll probably want to calculate the netmask upfront, like

n = ipaddress.ip_network('192.0.0.0/16')
netw = int(n.network_address)
mask = int(n.netmask)

Then, for each address, calculate the binary representation with one of

a = int(ipaddress.ip_address('192.0.43.10'))
a = struct.unpack('!I', socket.inet_pton(socket.AF_INET, '192.0.43.10'))[0]
a = struct.unpack('!I', socket.inet_aton('192.0.43.10'))[0]  # IPv4 only

Finally, you can simply check:

in_network = (a & mask) == netw