Python specifying IP format as input

Question

I am writing a simple client and server and want to introduce some simple bounds checking to insure the IP address entered by a user is in the correct format i.e.(int.int.int.int), does anybody have any suggestions as to hwo this can be done at the moment my code just accepts the value and will throw an OS error if its invalid. But I want to stop a user being able to enter anything in here.

 def ipEntered():
          global ipEntered
          ipEntered = input("Please enter the ip address of the server you wish to connect with:")

Thanks

Answer 1

Use the ipaddress module (introduced in Python 3.3):

import ipaddress

def ipEntered():
    while True:
        try:
            val = input("Please enter the ip address of the server you wish to connect with:")
            return ipaddress.ip_address(val)
        except ValueError:
            print("Not a valid IP address")

which will accept IPv4 addresses of the form "100.200.30.40", e.g. a dotted quad, and IPv6 addresses in both longhand form (8 groups of 4 hexadecimal characters separated by :) and shorthand forms.

If you only want to accept IPv4 addresses, use return ipaddress.IPv4Address(val) instead.