DHCP DNS Setup for small network

Question

I have a small network of 20 computers and 3 servers. I current have a Sonicwall firewall that does the DHCP for me. The question I have is the following.

On the DHCP settings should I have the local DNS server as the DNS server or should I use another one?

Current I use the local DNS server, but sometimes when I reboot one of the servers the other computers become very slow on the internet, and when the server is back up it all goes back to normal.

I have a domain controller that windows 2003 server, a secondary DNS server that is windows 2008 R2.

Thanks,

Answer 1

A local DNS server will cache results from all the workstations using it. So, if many of your staff visit the same sites often, it can speed up DNS queries since they won't have to go to the Internet to get results. When a workstation has multiple DNS servers in its config, it only uses the first one until no response is received (server is down). At that point, the workstation will switch to the second DNS server and remain there until it is no longer responsive or until the workstation is rebooted. So, it sounds like the secondary DNS server is having major issues. Another note, I would not recommend forwarding your DNS server to any Internet DNS server like google because you are then relying on that server to be up and have the right records. Configure your server to use root hints instead when no forwarders are available. This will force the server to resolve queries itself recursively.

Answer 2

The simplest configuration is to keep the DNS-Server on the same machine where the DHCP server is. Also set a public DNS server like the google dns server (8.8.8.8) on the primary DNS server so it can forward requests which are determinated to the internet. Make sure that also on the secondary DNS server is a DNS server configured which does not depend on your primary DNS server.

hope that helps.

Answer 3

I would suggest using OpenDNS for as your DNS server. You can configure it at server side to manage clients requests, alternatively with a network this small you could always configure DNS manually on the clients.

OpenDNS provides a very reliable services with added security, I also find the spell checking URL function good.

IP Addresses;

208.67.222.222 208.67.220.220