• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 350
  • Last Modified:

Alternate DNS Servers for Windows Server

Not sure that I can explain this well but, if I want to have my ISP's DNS servers included in a Windows Server 2003 DNS server how do I add them? I am trying to duplicate a previous setup where two ISP DNS servers were included before a PDC failed. BDC is providing services but does not pass these additional DNS servers to the workstations.

2 Solutions
DanielTAuthor Commented:
This is what I thought and had been looking at forwarders but, I did not have the server name. I see (now) that I can use the IP address as the name as well and will give it a shot.

JohnBannonIT ManagerCommented:
Use the Server manager, connect to internet wizard
Protect Your Employees from Wi-Fi Threats

As Wi-Fi growth and popularity continues to climb, not everyone understands the risks that come with connecting to public Wi-Fi or even offering Wi-Fi to employees, visitors and guests. Download the resource kit to make sure your safe wherever business takes you!

DanielTAuthor Commented:

Thanks. Got things working.
There was only one web site (reported) that was affected but it was certainly a DNS issue and it works now.

Puzzled by something though...
an IPCONFIG /ALL at any of the workstations would previously report two internal servers, the main router and two ISP DNS servers. This is not the case now but DNS seems to be working. Why/How are the additional DNS servers passed to the workstations?

Bruno PACIIT ConsultantCommented:

No, the additional DNS server SHOULD NOT and MUST NEVER be passed to the workstations.

Your worsktation MUST ONLY interrogate your internal DNS serverr.
What happen when you declare forwarders on a DNS server is that this DNS server is now able to retransmit a request to the forwarders if it is unable to resolve itself.

So, here are the steps that occurs when a worstation asks for an external DNS name:

1) The workstation send a DNS request for the external anme to your internal DNS server.
2) The internal DNS server receives the DNS request and read it. As the DNS server doesn't hosts the DNS zone matching the request, and as it has DNS forwarders configured it transmit the DNS resquest to the forwarders which are the external DNS servers.
3) The external DNS server receives the DNS request and resolves it. It sends back the response to the internal DNS server that has sent the request.
4) The internal DNS server receives the response from the external DNS server. It keeps this response in its local DNS cache and sends the response to the workstation.

As you can see, the workstation NEVER dialog with external DNS servers, and that is the only good way to do DNS internal/external resolution.

Have a good day.
DanielTAuthor Commented:
That actually makes a great deal of sense and is exactly what I would expect!
Thanks MUCH for the clarification.

I was puzzled as to how/why the 'failed' server was doing this.
It was the PDC and was handling DHCP, DNS etc.
How would workstations be receiving this info?

Here's an example of what I would see in an old IPCONFIG /ALL check...
(.50 and .51 were the servers)

Ethernet adapter UACoffice:
       Connection-specific DNS Suffix  . : xxxxx.office
        Description . . . . . . . . . . . : Intel(R) 82567LF-2 Gigabit Network Connection
        Physical Address. . . . . . . . . : 00-1C-C0-xx-XX-XX
        Dhcp Enabled. . . . . . . . . . . : Yes
        Autoconfiguration Enabled . . . . : Yes
        IP Address. . . . . . . . . . . . :
        Subnet Mask . . . . . . . . . . . :
        Default Gateway . . . . . . . . . :
        DHCP Server . . . . . . . . . . . :
        DNS Servers . . . . . . . . . . . :

Do you know why I would not be seeing ONLY .50 and .51 as DNS Servers vs also the router and the external xxx.153 addresses?
Bruno PACIIT ConsultantCommented:

Looking at the IPCONFIG result, DNS servers used by the computer come from the DHCP server.

Somewhere in the DHCP ranges settings you probably have added these 5 DNS servers.

Don't forget that in DHCP you can set a DNS server list in the IP range extended options, but ALSO in the DHCP server extended options.
So if you have configure some DNS servers on the DHCP IP range options, and other DNS servers on the DHCP server options you DHCP client will receive all these DNS servers.

Have a nice day
DanielTAuthor Commented:
From your previous comment then, this is not a good way to configure, right? I did not setup that server and since it has since failed, cannot check to see where it was setup per your advice (but thanks!).

If the DHCP forwarding should be used for clients to resolve external addresses what would this setup be used for? (assuming it even should be at all) This is what prompted mu initial question as I was not sure how the workstations were receiving the additional DNS server info but I pretty much knew it was from

DanielTAuthor Commented:
Thanks for everyone's input. Would still like to know about that last question but it is not important relative to the thread.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

On-Demand: Securing Your Wi-Fi for Summer Travel

Traveling this summer?Check out our on-demand webinar to learn about the importance of Wi-Fi security and 3 easy measures you can start taking immediately to protect your private data while using public Wi-Fi. Follow us today to learn more!

Tackle projects and never again get stuck behind a technical roadblock.
Join Now