[Okta Webinar] Learn how to a build a cloud-first strategyRegister Now

x
?
Solved

DNS question from DNS Noob

Posted on 2006-04-20
4
Medium Priority
?
183 Views
Last Modified: 2010-04-18
I currently have a SBS 2003 server with DNS serving our internal domain and forwarding unknown domain requests to our ISP's servers. This is OK until our ISP's servers go down or have problems (yes, it has happened!). What I would like to do is implement caching on our server so that even if our ISP's DNS servers go down, we can at least have some DNS functionality (albeit out of date until the ISP DNS server comes back online)

How do I go about doing this? What are the risks?
0
Comment
Question by:5t34lth_G33k
  • 2
4 Comments
 
LVL 85

Expert Comment

by:oBdA
ID: 16499325
If your ISP is unreliable, you can just remove the forwarders completely; the DNS server will then query the root DNS servers.
0
 
LVL 15

Expert Comment

by:markpalinux
ID: 16504421
Hello,

oBda has the right answer here. You do not have to turn on caching - it is there by default.  If you look at the SOA record for a DNS zone - it tells the DNS servers how long the dns information should be cached, etc.

So there are no steps to "implement caching" - just use the DNS server built into Windows 2003 server.

If you use DNS Admin Console, turn on the advanced viewm then you should be able to see the cached data.

Some or many of the cached zones may only show NS record "name server" records, that simply means that only the name server records are still cached, any hosts or A record had expired.  

Mark
0
 
LVL 7

Author Comment

by:5t34lth_G33k
ID: 16505115
So how is it then that when our ISP's DNS servers go down, we get page cannot be displayed errors? Surely if caching is on be default, our DNS server should look to its cache when its forwarders are unavailable?
0
 
LVL 15

Accepted Solution

by:
markpalinux earned 1500 total points
ID: 16509251


Make sure that the Root Hints tab has the root dns servers.



When you take out the forwarders your DNS server will use root hints -

example - user tries to get to www.rmhc.com 
1) the dns query is sent to your server
2) server checks its cache
3) server check for dns forwarders - none.
4) server checks the root dns server - per the root hints tab (a-m for a total of 13) to find the DNS servers "NS record" for the specific domain the dns query is for. : gets answer that name server is - ns1.rmhc.com = x.x.x.x
5) server sends query for A "host" record to ns1.rmhc.com - gets answer www=  ip address x.x.x.x
6) server caches the NS answer and the A record
7) server sends answer to the computer that sent the query


For more look at:

How DNS query works
http://technet2.microsoft.com/WindowsServer/en/Library/0bcd97e6-b75d-48ce-83ca-bf470573ebdc1033.mspx

DNS root hints reappear after being removed from in Windows Server 2003
http://support.microsoft.com/kb/875547/en-us


Mark
0

Featured Post

Transaction-level recovery for Oracle database

Veeam Explore for Oracle delivers low RTOs and RPOs with agentless transaction log backup and transaction-level recovery of Oracle databases. You can restore the database to a precise point in time, even to a specific transaction.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

by Batuhan Cetin In this article I will be guiding through the process of removing a failed DC metadata from Active Directory (hereafter, AD) using the ntdsutil tool in a Windows Server 2003 environment. These steps are not necessary in a Win…
Restoring deleted objects in Active Directory has been a standard feature in Active Directory for many years, yet some admins may not know what is available.
Is your data getting by on basic protection measures? In today’s climate of debilitating malware and ransomware—like WannaCry—that may not be enough. You need to establish more than basics, like a recovery plan that protects both data and endpoints.…
Loops Section Overview

873 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question