How to get host name from IP address using Python

One of the ways to identify a public IP address is to translate it to an associated host or domain name. This could be done by performing reverse IP lookup to the DNS servers.

The socket module provides IP-related functionalities in Python with gethostbyaddr function allows you to get the host name of an IP address.

1. Launch your preferred Python shell.

   $ ipython3
   Python 3.8.2 (default, Apr 27 2020, 15:53:34)
   Type 'copyright', 'credits' or 'license' for more information
   IPython 7.13.0 -- An enhanced Interactive Python. Type '?' for help.

2. Import socket module.

   In [1]: import socket

3. Use socket.gethostbyaddr to get host name from an IP address.

   In [2]: socket.gethostbyaddr('93.184.216.34')
   Out[2]: ('www.example.com', [], ['93.184.216.34'])

   Hostname in this context refers to Fully Qualified Domain Name or FQDN.

4. Create a Python script that accepts an IP address as parameter and outputs corresponding host information.

   ip-to-hostname.py

   #!/usr/bin/env python3
    
   import socket
   import sys
    
   address = sys.argv[1]
   host = socket.gethostbyaddr(address)
    
   print('Address: ', address, '\n' 'Host: ', host)

5. Run the script from the command line and provide an IP address as a parameter.

   $ python3 ip-to-hostname.py 216.58.196.4
   Address:  216.58.196.4
   Host:  ('kul08s09-in-f4.1e100.net', [], ['216.58.196.4'])