DNS Design Questions

[Deepseadata]

Hi there,

I need to figure out what device I should use as my DNS server.

Can I ask a couple questions?


Question 1:

I have a Cisco router connected to a satellite internet connection. I have a SBS connected to one of my local Vlans.

I don't want extra DNS requests on my WAN so I've been told that I should use my SBS as the DNS address.

Is it possible to point my SBS at my ISP's DNS's and then point my router back to my SBS as its DNS address?

My router is the DHCP server so I'd just give the SBS to them as the DNS maybe?

Question 2

This one is for Primary and Secondary DNS. If I use my Cisco's (internet router) DHCP to send clients the SBS as a primary DNS everyone will lose internet service if the SBS goes down.

Can I use the SBS as the primary DNS and the Cisco as a secondary DNS?

I'm going to read this article again to make sure I understand the Cisco side...

http://www.nil.si/ipcorner/RouterDNS/

 

[elmurado]

If you setup dhcp and dns on the sbs then you should be able to use the dhcp server options to set router and isp dns servers etc so that all clients get this info.


How many clients have you got? Secondary DNS is probably not that necessary unless you're generating heaps of requests.

 

[Deepseadata]

Thanks for the reply!

What I have done is create DHCP pools on my internet router that point all clients to the net for DNS.

What I want to do is use my DHCP server to point clients at the SBS. I don't have much SBS skills and my cisco router's DHCP is working. I'm just afraid that it might generate extra WAN traffic due to DNS issues, is that true?

I don't have the equipment infront of me so I can't test stuff at the moment. I just hope it is possible or adviseable to have my router point at a device on it's LAN port to find a DNS.

Actually, does the router need to find dns? The SBS does, and the clients are pointed at the SBS... so maybe it doesn't matter if the router has or hasn't got proper DNS?

Thanks again for reading Elmurado.

 

[technome]

Actually, does the router need to find Dns?"
Follow Elmurado's advice, place DHCP and DNS on the server, your just adding an extra point of failure placing the DHCP on the cisco. No the Cisco does not need DNS, unless it has a mind of it's own, and is cruising the Internet.

For added DNS security use Forwarders, you do not want DNS requests going to just any server on the Internet, use known DNS servers as a buffer between your system and rouge DNS servers.
Within the OS DNS properties, Forwarders, place your ISP's DNS servers as entries, add two more DNS server entries form another ISP... the extra DNS entries are in case your ISP screws up their servers or for some other reason access to the servers are down.


........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[Deepseadata]

I'll look into making the SBS the DHCP server I guess.

The thing was that I have a lot of "guests" that don't use the domain controller at all.

Most important is internet. I was trying to assure the internet would work even if the SBS got screwed up. No doubt, If the router dies internet dies. But If clients are pointed to SBS for DNS and there's a problem, everything dies even though the internet is still there.

I'm planning on using my ISP-supplied DNS addresses. I never thought of using any others but I'll look into that, too.

Thanks for the opinion, Technome.

 

[58sniper]

You must use forwarders. DNS queries should not be going to the root servers from an ordinary server.

Configure DNS and DHCP on the server as mentioned. Point DHCP back to the server for DNS. Configure DNS forwarders for your ISP's DNS server. Problem solved, and done so as designed.

Don't configure DNS on your router. Don't configure DHCP on your router. By having SBS do it, the clients will be correctly configured in DNS automatically as part of the DHCP lease.

Also, there is an SBS forum here for more answers.

Pat Richard MVP
Plan for performance, and capacity takes care of itself. Plan for capacity, and suffer poor performance.

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