Solved

Is there a way to prevent DNS lookups?

Posted on 2011-03-14
10
213 Views
Last Modified: 2012-05-11
I have a system that a previous administrator "disabled" internet access on. Now we want it to have internet access, but I can't figure out how they did it. Here are the symptoms:

PC is configured for DHCP and receives an IP address and correct DNS entries.
PC can ping and tracert to any IP address.
PC cannot ping or trace to an external hostname: "could not find host XXXX"
PC can use nslookup to resolve domain names.

I'm thinking there is a registry key or some connection specific setting that was changed to prevent this. I can't figure out what is causing this issue.
0
Comment
Question by:leviatdr
  • 5
  • 4
10 Comments
 
LVL 3

Expert Comment

by:vervenetworks
ID: 35132375
The easiest way to prevent internet access is the use of a proxy server in Internet Explorer.  Open IE, find Internet Options, typically under Tools or Privacy depending on the version.  Then to to Connections tab, and LAN Settings.  Uncheck the proxy if checked, and test.
0
 

Author Comment

by:leviatdr
ID: 35132451
I already checked that and there is no proxy set.
0
 
LVL 3

Expert Comment

by:vervenetworks
ID: 35132474
Is the primary DNS server on the PC internal to the network?  It may be using some type of DNS proxy through forwarding, such as OpenDNS.  You could try setting DNS to an external server, and test from there to see if the problem lies with the server.
0
 

Author Comment

by:leviatdr
ID: 35132809
Primary DNS is on the same network. I set the DNS server to both the local dns server and resolver1 at opendns. Same results. I can nslookup but not ping by hostname.
0
 
LVL 3

Expert Comment

by:vervenetworks
ID: 35133170
Does the server exhibit the same behavior as the workstation?
0
U.S. Department of Agriculture and Acronis Access

With the new era of mobile computing, smartphones and tablets, wireless communications and cloud services, the USDA sought to take advantage of a mobilized workforce and the blurring lines between personal and corporate computing resources.

 

Author Comment

by:leviatdr
ID: 35133258
No, the server and other local workstations resolve names just fine.

After digging through the event viewer, I'm finding Userenv ID 1054: "cannot obtain the domain controller name for your network, an invalid argument was supplied". I know this is a DNS issue, but I can't figure out why nslookup works but standard resolution doesn't. Does NSLookup bypass the local resolver?
0
 
LVL 3

Accepted Solution

by:
vervenetworks earned 250 total points
ID: 35133289
You may try to reset the TCP/IP stack using WinSockFix http://www.softpedia.com/get/Tweak/Network-Tweak/WinSockFix.shtml

NSLOOKUP does bypass the local DNS cache, and directly queries the primary DNS server.  You can specify an alternate server by using the command "server <servername or IP>"  My bet is a broken stack.  Any antivirus software or local firewall software you could try disabling as well temporarily.
0
 
LVL 26

Assisted Solution

by:akahan
akahan earned 250 total points
ID: 35134969
If you go to

Control Panel / Network Connections , right-click on the NIC you're using, choose Properties, choose Internet Protocol (TCP/IP), click the Properties button, click the Advanced button, and then the DNS tab, do you see anything unusual?

Tried uninstalling and reinstalling the NIC?  Uninstalling and reinstalling the TCP/IP protocol?
Ensuring that the firewall is not blocking UDP packets to port 53?
0
 

Author Comment

by:leviatdr
ID: 35138640
Winsock fix did not resolve the issue. I'm going to try reinstalling the NIC to see if that helps.
0
 

Author Closing Comment

by:leviatdr
ID: 35159608
Issue unresolved. User formatted machine. Thanks for trying.
0

Featured Post

DevOps Toolchain Recommendations

Read this Gartner Research Note and discover how your IT organization can automate and optimize DevOps processes using a toolchain architecture.

Question has a verified solution.

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

Can I legally transfer my OEM version of Windows to another PC?  (AKA - Can I put a new systemboard in my OEM PC?) Few of us are both IT and legal experts but we all have our own views of Microsoft's licensing rules and how they apply.  There are…
cPanel is a Unix based web hosting control panel that provides a graphical interface and automation tools designed to simplify the process of hosting a web site. cPanel utilizes a 3 tier structure that provides functionality for administrators, rese…
You have products, that come in variants and want to set different prices for them? Watch this micro tutorial that describes how to configure prices for Magento super attributes. Assigning simple products to configurable: We assigned simple products…
A company’s greatest vulnerability is their email. CEO fraud, ransomware and spear phishing attacks are the no1 threat to a company’s security. Cybercrime is responsible for the largest loss of money to companies today with losses projected to r…

919 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

Need Help in Real-Time?

Connect with top rated Experts

15 Experts available now in Live!

Get 1:1 Help Now