Let's take some time to reflect on the importance of a DNS service. It's what translates website names like cisco.com into the IP addresses computers need to find them. If this system breaks down, nothing works – applications stop, employees can't do their jobs, and the business grinds to a halt. But DNS isn't just about keeping things running; it's also a key spot to stop cyber threats. This article will show you a solid way to set up DNS using Cisco Umbrella Virtual Appliances (VAs) to make it both reliable and secure.
Why DNS Matters So Much (and What Can Go Wrong)
Almost every time you click a link or open an app, DNS is working behind the scenes. It's absolutely essential. Because of this, it's also a big target for attackers. If your DNS service is compromised, it can lead to catastrophic network outages. But even beyond just outages, attackers can use DNS to trick users into visiting malicious websites or connecting to harmful servers. This is where Cisco Umbrella steps in. It turns DNS from just a simple lookup service into a powerful security layer, actively blocking access to known bad domains (like those hosting malware or phishing sites) before your users can even connect to them. So, when we talk about DNS, we need to make sure it's not just a resilient system designed to overcome unexpected failures, but also a proactive security guard for your network.
Designing a Strong DNS Service with Cisco Umbrella
Our suggested setup combines Cisco Umbrella's cloud security with local virtual appliances and load balancing. This creates a DNS system that can withstand failures and keep your network safe. Here’s a look at how it works:
How the Key Parts Work Together:
-
Cisco Umbrella Virtual Appliances (VAs):
- What they do: These are virtual machines you install on your network (like VA1, VA2). They act as local DNS forwarders, meaning they handle DNS requests right there. They're smart enough to tell the difference between internal and external domain names, and they make sure those requests get sent to the right place.
- Why they're good: They secure the DNS traffic that leaves your network for Umbrella, encrypting it to prevent man-in-the-middle attacks. This also lets Umbrella see important details about your internal network, giving you better visibility into what's happening and more precise control over your security rules. Having more than one VA means if one goes down, the others can take over.
-
DNS Load Balancer (VIP LB):
- What it does: This sits in front of your Umbrella VAs. Its job is to spread DNS requests between VA1 and VA2. It also constantly checks if each VA is working correctly, creating a fallback system: if one VA fails, it automatically directs all traffic to the healthy one.
- Why it's good: It makes sure your DNS is always available. If one VA stops responding, the load balancer automatically sends requests to the VAs that are still working, so no one notices a problem.
-
Internal DNS Servers (DNS1, DNS2):
- What they do: These are your own DNS servers that know about your internal network addresses (like
fqdn.internal.com.br). The Umbrella VAs are set up to send any requests for these internal addresses to these servers.
- What they do: These are your own DNS servers that know about your internal network addresses (like
-
Cisco Umbrella Global and Alternate Resolvers:
- What they do: For any requests going outside your network (like
fqdn.external.com.br), the Umbrella VAs send them to Cisco Umbrella's main resolvers (208.67.220.220,208.67.222.222). We also set up alternate Umbrella resolvers (208.67.222.220,208.67.220.222) – notice how these are similar but distinct IP addresses – ready to step in if needed. - Why they're good: This provides extra reliability for external lookups and uses Umbrella's global threat intelligence to block dangerous external sites.
- What they do: For any requests going outside your network (like
What You Gain from This Setup:
- Reliability: With multiple VAs, a load balancer, and both primary and backup external resolvers, your DNS system is much less likely to fail. This means your critical applications and services stay online.
- Better Security at the DNS Level: By sending DNS traffic to Cisco Umbrella, you get protection against malware, phishing, and other web threats. It often stops these threats before they can even connect to your network.
- Handles Internal and External Requests Easily: This design manages both your internal and external DNS needs without complicated settings on every user's device. It simplifies network setup and keeps security consistent.
- Easy to Manage and See What's Happening: Cisco Umbrella gives you one place to set up rules, see security alerts, and understand your DNS traffic across your whole organization.
Conclusion
Having a well-designed DNS service isn't just a nice-to-have anymore; it's a must for any modern business. By using Cisco Umbrella Virtual Appliances with load balancing and connecting them to your internal DNS, you can build a DNS infrastructure that not only stands strong against outages but also actively defends against a wide range of cyber threats. This approach turns DNS from a potential weak spot into a powerful first line of defense, keeping your business running and your data safe.
More Information:
