Command line network lookups and operations

This python tool implements pretty much same things as netcalc and netblocks libraries, but with minor differences in the way things are done.

The library is intended to be usable both as a command line tool netlookup and as a library from server code. Personally I use it for splitting IP ranges to subnets.

Installing

pip install netlookup

Command line tool netlookup basic usage

Following examples illustrate Usage of netlookup tool.

Lookup details for IPv4 host with CIDR mask and IPv6 subnet:

netlookup info 172.31.1.19/17 2c0f:fb50:4000::/56
             CIDR 172.31.0.0/17
          Netmask 255.255.128.0
          Network 172.31.0.0
        Broadcast 172.31.127.255
       First host 172.31.0.1
        Last host 172.31.127.254
      Total hosts 32766
             Next 172.31.128.0/17
         Previous 172.30.128.0/17
             Bits 10101100.00011111.00000000.00000000
      Reverse DNS 0.0.31.172.in-addr.arpa.
             CIDR 2c0f:fb50:4000::/56
          Netmask ffff:ffff:ffff:ff00::
          Network 2c0f:fb50:4000::
        Broadcast 2c0f:fb50:4000:ff:ffff:ffff:ffff:ffff
       First host 2c0f:fb50:4000::1
        Last host 2c0f:fb50:4000:ff:ffff:ffff:ffff:fffe
      Total hosts 4722366482869645213694
             Next 2c0f:fb50:4000:100::/56
         Previous 2c0f:fb50:3fff:ff00::/56
             Bits 0010110000001111:1111101101010000:0100000000000000:0000000000000000:0000000000000000:0000000000000000:0000000000000000:0000000000000000
      Reverse DNS 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.4.0.5.b.f.f.0.c.2.ip6.arpa.

Split subnet with defaults (to next smaller subnet / larger prefix):

netlookup split 172.31.1.19/17 2c0f:fb50:4000::/56
    172.31.0.0/18
    172.31.64.0/18
    2c0f:fb50:4000::/57
    2c0f:fb50:4000:80::/57

Split IPv4 subnets with specific prefix:

netlookup split --mask 19 172.31.1.19/17 172.31.5.39/17
    172.31.0.0/19
    172.31.32.0/19
    172.31.64.0/19
    172.31.96.0/19
    172.31.0.0/19
    172.31.32.0/19
    172.31.64.0/19
    172.31.96.0/19

Using the python library

Some practical examples for using the API where a CLI command is not yet available.

Create set of networks and show minimal merged CIDR prefixes to cover this range:

from netlookup.network_sets.base import NetworkSet
ns = NetworkSet()
ns.add_network('172.31.0.0/23')
ns.add_network('172.31.4.0/22')
ns.add_network('172.31.8.0/24')
ns.add_network('172.31.9.0/25')
ns.add_network('172.31.9.128/25')
print('\n'.join(str(x.cidr) for x in ns.merged))

Previous example returns

172.31.0.0/23
172.31.4.0/22
172.31.8.0/23

Using same example, remove one /29 from the result set

from netlookup.network_sets.base import NetworkSet
ns = NetworkSet()
ns.add_network('172.31.0.0/23')
ns.add_network('172.31.4.0/22')
ns.add_network('172.31.8.0/24')
ns.add_network('172.31.9.0/25')
ns.add_network('172.31.9.128/25')
print('\n'.join(str(x.cidr) for x in ns.substract('172.31.8.64/29')))

This example returns

172.31.0.0/23
172.31.4.0/22
172.31.8.0/26
172.31.8.72/29
172.31.8.80/28
172.31.8.96/27
172.31.8.128/25
172.31.9.0/24

Cloud vendor prefixes

This tool contains lookup caches for some cloud vendors. Currently supported vendors are:

• AWS
• Cloudflare
• Google Cloud
• Google Services

Note: Azure support was removed because their data is in a silly URL and I just don't care about them.

Example to load data for cloud vendor IP prefix lookups and save it to user specific cache directory ~/.config/netlookup.

Following command requires internet connection to update the prefix lists.

from netlookup.prefixes import Prefixes
ns = Prefixes()
print(ns.cache_directory)
ns.update()
ns.save()

Get prefixes for cloud vendors

Use the previously loaded cached cloud vendor IP prefix lookup and find some addresses.

>>> ns.find('3.81.2.1')
aws us-east-1 3.80.0.0/12

Similarly, you can get specific vendor network set and lookup address from there:

>>> ns.get_vendor('google').find('216.58.210.142')
google 216.58.192.0/19