Link to home
Start Free TrialLog in
Avatar of rmartes
rmartes

asked on

How to confirm DNS is setup correctly?

All of the sudden, our internet connection has become very slow and I think it has to do with our DNS configuration.   We have one domain 2008 R2 and very site is a DC controller used for file and print sharing.  In addition, we also have DHCP and DNS on each site.  How do I confirm that our DNS is setup correctly.   If I do a dns lookup, I am getting the following:

nslookup 127.0.0.1
DNS request timed out.
   time out was 2 seconds.

Server: Unknown
Address: ::1

Name: localhost
Address: 127.0.0.1

Is there a tool or command that I can run to assure all my DNS settings are right?

Thanks

Richie
Avatar of msidnam
msidnam
Flag of United States of America image

Are you doing the nslookup on the server? If so, you may want to check your forwaders. You can check this by right clicking your DNS server inside the Server Manager under roles. When you do this, select properties and then select the forwarders tab.I use my ISP's DNs servers as forwarders.

Usually the way DNS works, is you should have one or more DC's as a DNs server. All your workstation should point to them using DHCP. Then those DNS servers should have forwarders that point to outside DNs servers to resolve outside names.
Avatar of David Johnson, CD
Please elaborate on 'internet is slow".  Have you checked your bandwidth utilization at the internet endpoint .. a machine on your network may be hogging the internet connection.

When did this first start to become an issue?  As a test you could only plug 1 computer into the internet endpoint and go to speedtest.net and verify your connection speed
Avatar of rmartes
rmartes

ASKER

Sorry about that.  Our internet goes through our datacenter.   This became an issue about 2 weeks ago.    In short, I just need to confirm that my DNS settings are correct.  I will like to start in just one site and then take it from there.   I personally think it is a DNS issue on my end.  Again, every site as its own DNS/DHCP on DC and they all communicate with each other.  I have a DC NY, TAMPA, LA, SEATTLE, CHICAGO and so on.  They are all part of the same Domain
dns would mean that the site doesn't resolve.
i.e. nslookup google.com -- do you get a result? was the lookup reasonably speedy?
Avatar of rmartes

ASKER

This is what I am getting, so something has to be wrong.

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\administrator.BNB>nslookup google.com
DNS request timed out.
    timeout was 2 seconds.
Server:  UnKnown
Address:  ::1

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to UnKnown timed-out

C:\Users\administrator.BNB>
that confirms that your dns is pooched.   from the server go into dns and select monitoring and see if both items pass the test

while you are there check your forwarers
Avatar of rmartes

ASKER

ok - I'll need to download the DNS monitoring management pack on this DC controller and get back to you.  What specifically are you wanting me to check in the forwarders??
ASKER CERTIFIED SOLUTION
Avatar of msidnam
msidnam
Flag of United States of America image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Avatar of rmartes

ASKER

The forwarder was wrong, so I changed it as suggested and it is now doing a successful nslookup on google.com

C:\Users\administrator.BNB>nslookup google.com
Server:  UnKnown
Address:  ::1

Non-authoritative answer:
Name:    google.com
Addresses:  2607:f8b0:4004:803::1005
          173.194.121.5
          173.194.121.7
          173.194.121.0
          173.194.121.3
          173.194.121.14
          173.194.121.9
          173.194.121.6
          173.194.121.8
          173.194.121.4
          173.194.121.2
          173.194.121.1

I installed the DNS monitoring management pack on the server, but don't seem to see where to run it.