How To Set A Specific DNS Server Using Dns.Resolver In Python?

Using the nameservers Attribute

The dns.resolver module in Python lets you customize the DNS servers for queries through the nameservers attribute. This attribute is a list of IP addresses that the resolver will use as DNS servers.

To use a specific DNS server, you can change the nameservers attribute of a Resolver instance. This lets you override the default system DNS settings and send your queries to a server you choose.

How to Set a Specific DNS Server

1. Import dns.resolver: Import the dns.resolver module from the dnspython library.

2. Create a Resolver instance: Make a new Resolver object to use.

3. Set the custom DNS server IP: Add the IP address of your chosen DNS server to the nameservers attribute of your Resolver instance.

By following these steps, you can set dns.resolver to use a specific DNS server for your queries, giving you more control over your DNS resolution process.

import dns.resolver

# Create a new resolver instance
custom_resolver = dns.resolver.Resolver()

# Set a custom DNS server (e.g., Google's public DNS)
custom_resolver.nameservers = ['8.8.8.8']

# Use the custom resolver for a DNS query
result = custom_resolver.resolve('example.com', 'A')

# Print the results
for ip in result:
    print(ip)

Breaking Down the Code

Let's look at each line of the code example to understand how to set a DNS server using dns.resolver:

import dns.resolver

This line imports the dns.resolver module from the dnspython library, giving us access to its DNS resolution functions.

custom_resolver = dns.resolver.Resolver()

Here, we create a new instance of the Resolver class. This object will handle our DNS queries.

custom_resolver.nameservers = ['8.8.8.8']

This line sets the nameservers attribute of our custom_resolver to a list with the IP address of our chosen DNS server. We're using Google's public DNS server (8.8.8.8).

result = custom_resolver.resolve('example.com', 'A')

We use the resolve method of our custom resolver to query the DNS for 'example.com'. The 'A' parameter specifies that we're looking for IPv4 address records.

for ip in result:
    print(ip)

This loop goes through each IP address in the result and prints it.

Best practices for implementation:

1. Use a try-except block to handle DNS resolution errors.
2. Use multiple DNS servers for redundancy.
3. Check the DNS server's privacy policy when choosing a public DNS service.
4. Update the DNS server IP address if it changes.
5. Use clear variable names.

By following these practices, you can make your DNS resolution code more stable and easier to maintain.

result = custom_resolver.resolve('example.com', 'A', lifetime=5)