Python network

netknife.py

# Validate IP address
import socket
def valid_ip(ipaddress):
    try: 
        socket.inet_aton(ipaddress)
        return True
    except:
        return False
        

# Validate domain name
def valid_domain(domainstring):
    # Lookahead makes sure that it has a minimum of 4 (a.in) and a maximum of 255 characters
    # One or more labels (separated by periods) of length between 1 to 63, starting and ending with alphanumeric characters, and containing alphanumeric chars and hyphens in the middle.
    # Followed by a top level domain name (whose max length is 5 for museum)
    dpattern = '^(?=.{4,255}$)([a-zA-Z0-9]{,61}[a-zA-Z0-9]\.)+[a-zA-Z]{2,5}$'

    if re.match(dpattern, domainstring):
        return True
    else: 
        return False