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+--- Thread: Breakdown CIDR with netaddr (/thread-21583.html)
Breakdown CIDR with netaddr - wfsteadman - Oct-05-2019
Was wondering if anyone out here has created an IP based subnet script that will take a CIDR address and then break it down into all the subnets between the CIDR mask and say a /24 Like this: 100.114.208.0/22
This would be the expected output:
100.114.208.0/22
--> 100.114.208.0/23
----> 100.114.208.0/24
----> 100.114.209.0/24
--> 100.114.210.0/23
----> 100.114.210.0/24
----> 100.114.211.0/24
100.114.212.0/22
--> 100.114.212.0/23
----> 100.114.212.0/24
----> 100.114.213.0/24
--> 100.114.214.0/23
----> 100.114.214.0/24
----> 100.114.215.0/24
Below is the code I have so far and I am missing something because the output is incorrect and I can't figure out why...
#!/usr/bin/env python
from netaddr import IPAddress, IPNetwork
def cidr_range(ip, max=24):
print('Starting subnet: %s/%d' % (ip.ip, ip.prefixlen))
cidr(ip.ip, ip.prefixlen, max)
def cidr(ip, width, max):
if width > max:
return
print('%s/%d' % (ip, width))
cidr(ip, width+1, max)
i = ip.value | (1 << (32-width-1))
ip2 = IPAddress(i)
print('%s/%d' % (ip2, width))
cidr(ip2, width+1, max)
cidr_range(IPNetwork('100.114.208.0/22'))These are the results I am getting and I am sure it has something to do with how I am recursing, but since I am new to using netaddr and have always been muddy on recursion I can't see what is going wrong.100.114.208.0/21
100.114.208.0/22
100.114.208.0/23
100.114.208.0/24
100.114.208.128/24
100.114.209.0/23
100.114.209.0/24
100.114.209.128/24
100.114.210.0/22
100.114.210.0/23
100.114.210.0/24
100.114.210.128/24
100.114.211.0/23
100.114.211.0/24
100.114.211.128/24
100.114.212.0/21
100.114.212.0/22
100.114.212.0/23
100.114.212.0/24
100.114.212.128/24
100.114.213.0/23
100.114.213.0/24
100.114.213.128/24
100.114.214.0/22
100.114.214.0/23
100.114.214.0/24
100.114.214.128/24
100.114.215.0/23
100.114.215.0/24
100.114.215.128/24
Any assistance would be appreciated.
TIA
Wally
RE: Breakdown CIDR with netaddr - wfsteadman - Oct-06-2019
I got it working using this:
from netaddr import *
import sys
network_list = []
subnet_list = []
def define_prefixlens(subnet_input, max):
max_cidr_val = int(max) + 1
ip = IPNetwork(subnet_input)
prefixes = (i for i in range(ip.prefixlen +1, max_cidr_val))
for i in prefixes:
network_list.append(i)
def list_of_subnets(subnet):
ip = IPNetwork(subnet)
for i in network_list:
sub = ip.subnet(i)
for i in sub:
subnet_list.append(i)
def main():
# value = sys.argv[1]
value = '10.20.30.0/27'
# max_cidr = sys.argv[2]
max_cidr = 24
define_prefixlens(value, max_cidr)
# print(network_list)
list_of_subnets(value)
for i in sorted(subnet_list):
print(i)
if __name__ == '__main__':
main()