DNS translates domain names to their corresponding IP addresses. Typically, ISPs run DNS servers, and devices perform DNS lookups to determine the server address to contact. However, running your own DNS server can give you more control over your network and improve performance. Here's how to set up a DNS server on Linux using Dnsmasq, a lightweight DNS server that's easy to configure.
What Is DNS?
DNS is a system that translates domain names like example.com to their corresponding IP addresses, like 127.0.0.1. Every network request that uses a domain name requires a DNS lookup, which adds an overhead to each request. ISPs typically run DNS servers, and public DNS servers are available from providers like Cloudflare and Google.
Why Run Your Own DNS?
Running your own DNS server can provide you with more control over your network, including network-level domain mappings, and allows you to centralize settings in one location. It can also improve performance and provide an extra layer of resilience during DNS outages.
DNS With Dnsmasq
Dnsmasq is a lightweight DNS server that's included with most Linux distributions and is easy to configure. In this guide, we'll set up Dnsmasq with local caching, custom domain routes, and Google's 8.8.8.8 as the upstream DNS provider.
Getting Started
Assuming you have a functioning Linux machine ready to host Dnsmasq, ensure that it has a static IP assigned, and install Dnsmasq. The configuration file for Dnsmasq is typically located at /etc/dnsmasq.conf and comes pre-populated with initial settings.
Configuring Dnsmasq
To configure Dnsmasq, uncomment the following lines in the configuration file:
#domain-needed #bogus-priv
The "domain-needed" setting stops Dnsmasq from forwarding local names without a domain part to the upstream DNS server, while "bogus-priv" prevents forwarding DNS reverse-lookup queries to the upstream DNS server.
To set your upstream DNS server, add the following lines to your config file:
server=8.8.8.8 server=4.4.4.4
This instructs Dnsmasq to forward unresolved queries to Google's DNS service, using 8.8.8.8 as the primary resolver and 4.4.4.4 as the secondary resolver.
Next, adjust the cache size by finding and uncommenting the "cache-size" line in the config file. Increasing this value will allow Dnsmasq to serve more lookups from the cache, reducing network latency.
Conclusion
Setting up a DNS server using Dnsmasq on Linux is a straightforward process that provides more control over your network, improves performance, and provides an extra layer of resilience. By following the steps outlined in this guide, you can easily configure Dnsmasq to suit your needs.
