Can a Cisco router be a DNS server?

Can a router act as a DNS server?

Short Answer.

No, but a router's external interface can act as one of the DNS resolvers provided in the OS. You can access the external interface DNS to do name resolution on the LAN.

A router typically provides several services including access to the Internet for IP-based applications, an internal network, and many others. One of the most basic, and yet fundamental, functions that a router provides is a name server (DNS).

The IP address of a device on a local area network (LAN) is assigned dynamically by the operating system, which resolves it with a resolver. If this resolver is a DNS server, then the resolver will return the name of the device from its directory (zone file). When the computer needs the name of a device on the network, the operating system performs a DNS query to resolve the IP address into a name. A device with a static IP address will be in the LAN domain, and its name will already be stored in its zone file. This also applies to a device on the public Internet. When the device wants to access an internal hostname such as www.google.com, the device queries the name server on the LAN to find the Internet IP address for www.com and uses that IP address to access the Internet. The LAN name resolution service has nothing to do with the public Internet name resolution service.

In this article, we will show you how a router can act as a DNS server and perform name resolution. However, before we begin, let's discuss the pros and cons of using a router as a DNS server.

Routers as DNS Servers. Advantages of using a router as a DNS server. Many routers have a built-in, embedded CPU with hardware name servers such as BIND and Unbound. In this case, there is no additional hardware required, and these router features can be used out of the box. These are referred to as "embedded" name servers because they are running on the embedded CPU and not the main operating system. This is different from "cloud" name servers, which are usually hosted on remote servers such as Amazon's AWS or Google's DNS Service, and use commodity servers such as Digital Ocean.

Some ISPs deploy custom DNS servers on their routers. These DNS servers are configured via WAN ports and are used for resolving names of sites hosted on external networks.

Can a Cisco router be a DNS server?

My friend is setting up his Cisco router with a small office-grade DSL connection (I'm not an IT pro, but I can set up a web server), and he's wanting to run a local DNS server on it. Is this possible? And if so, where can I find any documentation about how to do this? Thanks! You can, however this would be a very bad idea. You'd be trusting the cisco with your dns server, which means anyone who is connected to it can resolve domain names using that name for an authoritative nameserver in their own caching name server.

Can Cisco ASA act as DNS server?

We have a Cisco ASA which handles internet traffic for our home network.

We have setup static ip addresses and routing to specific subnets. We have also assigned IP addresses to a few devices that have been given static ip addresses (and are thus not part of the main pool). How can we let those devices talk to a server on a specific host? Do I need any special configuration in our ASA? Should it act as a DNS server? The devices I am talking about are an HP LaserJet, a Wifi router and a mobile phone.

I'm not familiar with Cisco ASA, but I think that your question can be answered with a yes or no answer. If yes, please elaborate more. If no, please elaborate why it won't work with DNS.

Martin HMar 14 '11 at 7:41. 1

Yes! The IPsec Security Association is already in place for the devices that connect to the ASFrom what I've read in various forums and Cisco forums, yes it will serve as a DNS server. Martin HMar 14 '11 at 7:48. So if you have static IPs for all devices connected to your ASA, does this mean that they will be able to reach a DNS server without configuring static DNS entries? SethMar 14 '11 at 9:04. 1

Cisco does not appear to provide its own "DNS" solution (that I know of). However, the "dns command" has limited use and probably not what you want for this use case. What you want to accomplish is likely possible without even doing static DNS entries; what the "dns command" does is resolve the ip address of the host (if you set the server-host option, that is).