Of course! In Python, the standard way to get the IP address from a hostname (a process also known as DNS resolution) is by using the socket module.

The primary function for this is socket.gethostbyname().

The Basic Method: socket.gethostbyname()

This function takes a hostname (like 'google.com' or 'python.org') and returns its corresponding IPv4 address as a string.

How to Use It

Here is a simple, complete example:

import socket
hostname = "google.com"
try:
    # Get the IP address for the hostname
    ip_address = socket.gethostbyname(hostname)
    print(f"The IP address of {hostname} is: {ip_address}")
except socket.gaierror as e:
    # gaierror stands for "getaddrinfo error"
    print(f"Could not resolve hostname {hostname}: {e}")
except Exception as e:
    print(f"An unexpected error occurred: {e}")

Output:

The IP address of google.com is: 142.250.191.78

Explanation of the Code

1. import socket: This line imports Python's built-in socket module, which provides access to the BSD socket interface.
2. hostname = "google.com": We define the hostname we want to look up.
3. try...except block: This is crucial for robust code. DNS lookups can fail for many reasons (the host doesn't exist, the DNS server is down, etc.), so you must handle potential errors.
   • socket.gethostbyname(hostname): This is the core function call. It performs the DNS query.
   • socket.gaierror: This specific exception is raised if the name resolution fails. gaierror stands for "get address info error". It's the most common error you'll encounter for an invalid hostname.

Getting More Information: socket.getaddrinfo()

Sometimes, you need more than just the IPv4 address. You might want the IPv6 address, or a list of all IP addresses associated with a host. For this, socket.getaddrinfo() is a more powerful and flexible function.

It returns a list of tuples, where each tuple contains a variety of information about a potential connection.

How to Use It

This function returns a lot of information. Let's break down how to use it.

import socket
hostname = "python.org"
try:
    # Get a list of address information for the hostname
    # We ask for all available addresses (AF_UNSPEC) and all types (SOCK_STREAM, SOCK_DGRAM)
    addr_info_list = socket.getaddrinfo(hostname, None, family=socket.AF_UNSPEC)
    print(f"Address information for {hostname}:\n")
    for info in addr_info_list:
        # Each 'info' tuple contains: (family, type, proto, canonname, sockaddr)
        family, type, proto, canonname, sockaddr = info
        # The sockaddr contains the actual address. Its format depends on the family.
        if family == socket.AF_INET:
            # For IPv4, sockaddr is (ip_address, port)
            ip_address = sockaddr[0]
            print(f"IPv4 Address: {ip_address}")
        elif family == socket.AF_INET6:
            # For IPv6, sockaddr is (ip_address, port, flowinfo, scopeid)
            ip_address = sockaddr[0]
            print(f"IPv6 Address: {ip_address}")
except socket.gaierror as e:
    print(f"Could not resolve hostname {hostname}: {e}")

Output:

Address information for python.org:
IPv4 Address: 51.222.160.227
IPv4 Address: 51.222.160.228
IPv6 Address: 2001:41d0:601:110::53
IPv6 Address: 2001:41d0:601:110::59

Explanation of getaddrinfo()

• socket.getaddrinfo(hostname, port, ...): It takes a hostname and a port number (or None if you don't care about the port).
• family=socket.AF_UNSPEC: This tells the function to return addresses for any family (both IPv4 and IPv6). You could specify socket.AF_INET for only IPv4 or socket.AF_INET6 for only IPv6.
• Return Value: A list of 5-tuples. The last element, sockaddr, holds the actual IP address and port. The format of sockaddr differs between IPv4 and IPv6, which is why we check the family in the loop.

The Reverse: Getting a Hostname from an IP Address

You can also do the reverse lookup using socket.gethostbyaddr().

import socket
ip_address = "8.8.8.8" # Google's Public DNS
try:
    hostname, aliaslist, ipaddrlist = socket.gethostbyaddr(ip_address)
    print(f"The hostname for IP {ip_address} is: {hostname}")
    print(f"Aliases: {aliaslist}")
    print(f"IP addresses: {ipaddrlist}")
except socket.herror as e:
    # herror stands for "host error"
    print(f"Could not resolve hostname for IP {ip_address}: {e}")

Output:

The hostname for IP 8.8.8.8 is: dns.google
Aliases: []
IP addresses: ['8.8.8.8']

Summary: Which one should you use?