Why You Need a DNS Cache Server

In today’s fast-paced digital world, where information is accessed at lightning speed, every millisecond counts. Network latency, the delay in data transmission, can significantly impact user experience. One often-overlooked culprit of latency is DNS resolution – the process of converting domain names (like roosho.com) into IP addresses (like 157.240.1.35) that computers understand.

Imagine a bustling office where employees rely heavily on the internet for their daily tasks. Slow-loading websites and sluggish applications can lead to frustration and decreased productivity. Or consider a gaming environment where split-second decisions can mean the difference between victory and defeat. Network latency, often caused by DNS resolution delays, can be a significant hindrance.

A DNS cache server acts as a local directory for your network, storing recently resolved domain names and their corresponding IP addresses. When a device on your network requests to access a website, the cache server checks its local records first. If the information is found, it’s provided instantly, bypassing the need to contact external DNS servers. This dramatically reduces lookup times, resulting in faster website loading speeds, improved application performance, and a smoother overall internet experience.

Case Study: NIILAA – Boosting Productivity with a DNS Cache Server

The Challenge

At NIILAA, an IT firm with 60 employees, we were grappling with increasing complaints about slow internet speeds, frequent application hang-ups, and sluggish email performance. Initially, my team and I thought these issues stemmed from network congestion or outdated hardware. However, a thorough investigation revealed that delays in DNS resolution were a major contributing factor.

Our employees were spending too much time waiting for websites to load, emails to send, and software updates to download. This not only hindered productivity but also frustrated our staff, leading to decreased morale.

The Solution

To tackle these problems, we at NIILAA decided to implement a DNS cache server. I installed BIND9 and configured it to use reliable forwarders (google and Cloudflare DNS). Our goal by caching DNS records locally was to reduce latency, improve application performance, and enhance overall network responsiveness.

The Results

The deployment of the DNS cache server marked a dramatic turnaround in network performance at NIILAA. Employees reported significantly faster website loading times, smoother application performance, and a noticeable reduction in email latency. As a result, our company’s productivity soared as employees spent less time waiting for resources to load.

Furthermore, by taking control of our DNS resolution process, we were able to implement stricter security measures. I directed the IT team to configure the DNS cache server to block access to malicious websites, protecting our employees from phishing attacks and other online threats.

Key Benefits

• Improved Network Performance: We observed a 30% reduction in average DNS query response times, leading to quicker website loading and faster application launches.
• Enhanced Employee Productivity: Our employees experienced a 20% increase in productivity due to reduced wait times for accessing online resources.
• Strengthened Security: The DNS cache server effectively blocked access to known malicious websites, safeguarding our company data and preventing potential security breaches.
• Cost Savings: By optimizing network performance and reducing the load on our internet connection, we achieved cost savings on bandwidth and IT support.

Conclusion

Implementing a DNS cache server proved to be a highly effective solution for NIILAA’s network performance challenges. By addressing the root cause, DNS resolution delays, we significantly enhanced employee productivity, improved network efficiency, and strengthened security. This case study demonstrates the tangible benefits of deploying a DNS cache server in a corporate environment.

Advantages of a DNS Cache Server

A DNS cache server is essentially a local directory for your network, storing website addresses (IP addresses) for quicker access. This can significantly boost your internet speed and overall network performance.

Here are some key benefits:

• Accelerated Website Loading: When you visit a website, your device typically needs to ask a DNS server for the website’s IP address. With a local DNS cache, this information is often already stored, eliminating the need to wait for an external lookup. This translates to noticeably faster website loading times.
• Reduced Network Congestion: Fewer requests to external DNS servers mean less traffic on your network. This is beneficial for everyone sharing the network, as it improves overall performance and reduces latency.
• Enhanced Application Performance: Many online applications, from email to cloud storage, rely on DNS lookups. A local DNS cache can drastically improve the speed and responsiveness of these applications.
• Increased Privacy: By using a local DNS cache, you can reduce the amount of data your internet service provider (ISP) collects about your online activities. This is because your DNS queries are handled locally, rather than being sent to your ISP’s DNS servers.
• Fortified Security: A DNS cache server offers a layer of protection against DNS-based attacks. By controlling which DNS servers your network uses, you can filter out malicious domains and prevent users from accessing harmful websites. Additionally, caching DNS information from trusted sources can help mitigate the risks of phishing and other online threats.
• Potential for Offline Access: While not a guaranteed feature, under certain conditions, a DNS cache server can provide limited offline access to recently visited websites. This is possible because the DNS information for those sites is already stored locally. However, this functionality is dependent on the specific DNS software and configuration.

In essence, a DNS cache server can significantly enhance your network’s performance, security, and user experience.

How to Create a DNS Cache Server Using BIND9

Here’s a step-by-step guide to creating a Local DNS Cache Server on Ubuntu using BIND9. This tutorial will take you through the processes from preparing the operating system to verifying the DNS server functionality.

Gaining Root Access

We start by gaining root access. This grants us the necessary permissions to install and configure server components. However, wielding root privileges comes with inherent risks. It’s generally recommended to use sudo with the specific command you want to execute as opposed to sudo -i which switches your entire session to root. For instance, to update package lists with root access.

Before making any changes to your system, it’s essential to operate as the root user to ensure you have the necessary permissions:

sudo -i

If you frequently require temporary root access, consider using visudo to configure a more secure method tailored to your needs.

Preparing the OS with Updates and Upgrades

Before installing new software, it’s crucial to update the system’s package lists. This ensures you’re working with the latest versions of software available, which often include security patches and performance improvements. The apt-get update command refreshes the list of packages without actually installing or upgrading anything.

Ensure your operating system has the latest updates and security patches:

apt-get update

Following the update, we use apt-get upgrade -y to upgrade all installed packages to their most recent versions. The -y flag assumes acceptance of any prompts during the upgrade process, so be mindful of what’s being upgraded.

Upgrade your system with these updates:

apt-get upgrade -y

During the upgrade, you might be prompted to restart services that use outdated libraries. Ensure to review and confirm these to maintain system stability.

Installing the DNS Cache Server

Now comes the installation of BIND9, the software that will power our DNS cache server. BIND9 is a widely used and reliable choice for this purpose. We also install bind9utils and bind9-doc which provides additional utilities and documentation for managing the server.

Install BIND9, a robust and widely-used DNS server software, along with its utilities and documentation:

apt-get install bind9 bind9utils bind9-doc -y

Configuring the DNS Server

The next step involves editing the main BIND9 configuration file (/etc/bind/named.conf.options). Here, we define DNS forwarders. These are external DNS servers that BIND9 will rely on when it can’t resolve a domain name from its cache. Including reliable forwarders like Google’s (8.8.8.8) and Cloudflare’s (1.1.1.1) DNS servers enhances the efficiency of your local server. If BIND9 encounters a query it doesn’t have cached, it can efficiently delegate the resolution to these larger, more comprehensive servers.

Configure BIND9 by setting up DNS forwarders in its main configuration file:

nano /etc/bind/named.conf.options

Set up DNS forwarders to handle queries that the cache does not cover. Here’s an example configuration:

forwarders {
    8.8.8.8;  // Google's DNS
    8.8.4.4;  // Google's DNS
    1.1.1.1;  // Cloudflare DNS
};

Verifying Network Interface Configuration

After making configuration changes, it’s essential to restart the BIND9 service using systemctl restart bind9. This ensures the new configuration takes effect. Finally, we use systemctl status bind9 to verify that the service is running without errors. If there are any issues, the status command will provide clues, often indicating configuration errors or service failures. By checking the status, we can identify and address any problems before proceeding.

Apply the configuration changes by restarting BIND9 and check its status:

systemctl restart bind9
systemctl status bind9

Getting the DNS Address

It’s important to confirm the server’s IP address as it needs to be used by client devices for DNS queries.

Check the IP address of your DNS server:

ip addr

Configuring Client Devices – Pointing Them to the Server

To leverage our newly created DNS server, client devices within the network need to be configured to use it. The guide provides a detailed explanation on how to set this up for Windows clients. In essence, we’re directing the client devices to utilize our local DNS server for domain name resolutions. This can potentially improve browsing speed by reducing reliance on external DNS servers and also offers more control over how DNS queries are handled within your network.

To utilize the newly configured DNS server, client devices need to be pointed to it. Here’s how to configure a Windows client:

Accessing Network Settings

• Open the “Run” dialog (Win + R), type ncpa.cpl, and press Enter to open Network Connections.

Modifying the Ethernet Adapter Settings

• Right-click on your Ethernet connection and select “Properties”.

• Scroll to “Internet Protocol Version 4 (TCP/IPv4)” and click “Properties”.

Setting DNS Server Addresses

• Select “Use the following DNS server addresses”.
• Preferred DNS server: Enter the IP address of your BIND9 server, e.g., 10.10.10.10.

• Click “OK” to apply the changes.

Verifying the Configuration on the Client

Once the client device is configured, we need to confirm the changes took effect. The guide outlines how to use ipconfig /all on a Windows machine to verify that the DNS Servers entry points to the IP address of your BIND9 server. This step ensures that the client device is successfully communicating with your local server for DNS resolution.

To ensure the DNS settings are applied correctly:

• Open Command Prompt and run:

ip addr

• Check under the Ethernet adapter settings to see if the DNS Servers entry points to 10.10.10.10.

Testing DNS Resolution

The final step involves testing the functionality of your DNS server. Simply opening a web browser and navigating to a website will initiate a DNS resolution request. If the website loads successfully, it signifies that your local DNS server is operational and resolving domain names effectively.

Perform a DNS resolution test:

• Open a web browser and navigate to a website, e.g., roosho.com.

• Check if the site loads successfully, indicating that DNS resolution is functioning correctly through your local server.

Conclusion: A Functional Local DNS Server

By following these steps, you’ve successfully set up a DNS cache server using BIND9 and configured a client device to utilize it. This setup can offer several advantages, including potentially faster browsing speeds, increased control over network traffic, and potentially enhanced privacy by handling DNS requests locally. It’s important to remember that local DNS servers might require manual updates for local domain names, unlike relying on larger, constantly updated external servers.

roosho Senior Engineer (Technical Services)

I am Rakib Raihan RooSho, Jack of all IT Trades. You got it right. Good for nothing. I try a lot of things and fail more than that. That's how I learn. Whenever I succeed, I note that in my cookbook. Eventually, that became my blog. 

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