Find the IP Prefix that contains a list of IP addresses

Question

I have a list of IP addresses and I want to find the longest prefix that includes all of those IPs.

This is essentially the opposite of what the hosts function of the ipaddress module does:

https://docs.python.org/3/library/ipaddress.html#ipaddress.IPv4Network.hosts

I scanned the documentation for ipaddress and netaddr and couldn't find anything like that.

Answer 1

I expect you need something like netaddr.spanning_cidr:

In [1]: from netaddr import spanning_cidr

In [2]: list_of_ips = [
   ...:     '10.0.0.10',
   ...:     '10.0.0.11',
   ...:     '10.0.0.12',
   ...:     '10.0.0.13',
   ...:     '10.0.0.40',
   ...:     '10.0.0.43',
   ...:     '10.0.0.44',
   ...:     '10.0.0.45',
   ...:     '10.0.0.46',
   ...:     '10.0.0.47',
   ...:     '10.0.0.48',
   ...:     '10.0.0.49',
   ...:     '10.0.0.50',
   ...:     '10.0.0.51',
   ...:     '10.0.0.52',
   ...:     '10.0.0.53',
   ...:     '10.0.0.54',
   ...:     '10.0.0.55',
   ...:     '10.0.0.56',
   ...:     '10.0.0.57',
   ...:     '10.0.0.58',
   ...:     '10.0.0.59',
   ...:     '10.0.0.60',
   ...: ]

In [3]: spanning_cidr(list_of_ips)
Out[3]: IPNetwork('10.0.0.0/26')