How to check if network subnets are overlapping each other

Check if network subnets are overlapping each other.

Use ipconflict Python package (source) to check if two or more network subnets are overlapping.

Install ipconflict Pythopn package.

$ pip3 install ipconflict

Defaulting to user installation because normal site-packages is not writeable
Collecting ipconflict
  Downloading ipconflict-0.5.0-py2.py3-none-any.whl (16 kB)
Collecting py-radix
  Downloading py-radix-0.10.0.tar.gz (21 kB)
  Preparing metadata (setup.py) ... done
Requirement already satisfied: netaddr in /usr/lib/python3/dist-packages (from ipconflict) (0.8.0)
Collecting tqdm
  Downloading tqdm-4.64.1-py2.py3-none-any.whl (78 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 78.5/78.5 KB 1.3 MB/s eta 0:00:00
Building wheels for collected packages: py-radix
  Building wheel for py-radix (setup.py) ... done
  Created wheel for py-radix: filename=py_radix-0.10.0-cp310-cp310-linux_x86_64.whl size=50897 sha256=d170ed0f783ffe973e03530aabd4dd3ee1e00d3c4a260a90cfb9c8174843b6ad
  Stored in directory: /home/milosz/.cache/pip/wheels/6d/29/5a/e5083f47e00dd79bf1e95d93c452440cff80d7ca16215cabed
Successfully built py-radix
Installing collected packages: py-radix, tqdm, ipconflict
  WARNING: The script tqdm is installed in '/home/milosz/.local/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
  WARNING: The script ipconflict is installed in '/home/milosz/.local/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed ipconflict-0.5.0 py-radix-0.10.0 tqdm-4.64.1

Ensure that binary directory is in PATH.

$ echo $PATH

/home/milosz/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/snap/bin

$ export PATH=$PATH:~/.local/bin/

Update ~/.bashrc file accordingly.

Display help information.

$ ipconflict --help

usage: ipconflict [-h] [-f FROM_FILE] [-i] [-o] [-p] [-q] [-V] [subnets ...]

Check for conflicts between subnets.

positional arguments:
  subnets               list of subnets to be checked

options:
  -h, --help            show this help message and exit
  -f FROM_FILE, --from-file FROM_FILE
                        load subnet definitions from file (one per line)
  -i, --from-stdin      load subnet definitions from stdin
  -o, --ip-only         print only the overlapping IP addresses
  -p, --print-conflicts
                        print overlapping IP addresses
  -q, --quiet           show progress status
  -V, --version         print ipconflict version

examples:
  ipconflict 10.0.0.0/24 10.0.0.1/16
  ipconflict 10.0.0.0/24 10.0.0.20-10.0.0.25
  ipconflict -f my-subnets.txt
  ipconflict -f my-subnets.txt 192.168.0.0/24

exit status:
  0: one or more conflicts found
  1: no conflict found
  2: aborted or invalid input

Check two network subnets for conflicts.

$ ipconflict 172.16.26.0/23 172.16.27.64/26

100%|███████████████████████████████████████████| 2/2 [00:00<00:00, 13530.01subnet/s]
conflict found: 172.16.26.0/23 <-> 172.16.27.64/26

Inspect exit code.

$ echo $?

Use quiet mode.

$ ipconflict --quiet 172.16.26.0/23 172.16.27.64/26

conflict found: 172.16.26.0/23 <-> 172.16.27.64/26

Display conflicting IP addresses.

$ ipconflict --quiet --ip-only --print-conflicts 172.16.26.0/23 172.16.27.64/26

172.16.27.64
172.16.27.65
172.16.27.66
172.16.27.67
172.16.27.68
172.16.27.69
172.16.27.70
172.16.27.71
172.16.27.72
172.16.27.73
172.16.27.74
172.16.27.75
172.16.27.76
172.16.27.77
172.16.27.78
172.16.27.79
172.16.27.80
172.16.27.81
172.16.27.82
172.16.27.83
172.16.27.84
172.16.27.85
172.16.27.86
172.16.27.87
172.16.27.88
172.16.27.89
172.16.27.90
172.16.27.91
172.16.27.92
172.16.27.93
172.16.27.94
172.16.27.95
172.16.27.96
172.16.27.97
172.16.27.98
172.16.27.99
172.16.27.100
172.16.27.101
172.16.27.102
172.16.27.103
172.16.27.104
172.16.27.105
172.16.27.106
172.16.27.107
172.16.27.108
172.16.27.109
172.16.27.110
172.16.27.111
172.16.27.112
172.16.27.113
172.16.27.114
172.16.27.115
172.16.27.116
172.16.27.117
172.16.27.118
172.16.27.119
172.16.27.120
172.16.27.121
172.16.27.122
172.16.27.123
172.16.27.124
172.16.27.125
172.16.27.126
172.16.27.127

Check different networks.

$ ipconflict --quiet 172.16.27.0/26 172.16.27.64/26

no conflict found

$ echo $?

Additional notes

You can also display IP addresses for given network (172.16.29.48/28), but notice that the list includes network (first) and broadcast (last) address.

$ ipconflict --quiet --ip-only --print-conflicts 172.16.29.48/28 0.0.0.0/0

172.16.29.48
172.16.29.49
172.16.29.50
172.16.29.51
172.16.29.52
172.16.29.53
172.16.29.54
172.16.29.55
172.16.29.56
172.16.29.57
172.16.29.58
172.16.29.59
172.16.29.60
172.16.29.61
172.16.29.62
172.16.29.63

Calculate usable IP addresses for given network (172.16.29.48/28).

$ expr $(ipconflict --quiet --ip-only --print-conflicts 172.16.29.32/28 0.0.0.0/0 | wc -l) - 2

Additional notes#

Additional notes