Solved

I can't get out to a specific website

Posted on 2011-02-10
9
386 Views
Last Modified: 2012-05-11
Integrated Active Directory DNS 2003

We have a specific website we can't access from our internal network, but it can be accessed from outside of our network. It's not a web filter issue, it's a dns issue. If I use our internal DNS servers it doesn't work, but if I put in a static DNS like 4.2.2.2, then I can get to the site.

I need some ideas, on how to resolve this DNS issue...
0
Comment
Question by:bernardb
  • 5
  • 3
9 Comments
 
LVL 70

Expert Comment

by:Chris Dent
ID: 34865667
Using Forwarders or Root Hints? Root Hints is the default, but if you're not sure, pop open the Properties for your DNS server then select the Forwarders tab.

Perhaps the most common cause of obscure resolution failure is EDNS (Extended DNS). This happens because some routers / firewalls silently drop UDP packets larger than 512 bytes. EDNS is a change that means the server advertises support for packets over 512 bytes, if the network hardware doesn't support that as well you end up with trouble.

To test if this is the case, run:

dnscmd /config /EnableEDnsProbes 0

This disabled EDNS, once done, flush the cache with:

dnscmd /ClearCache

Then run:

nslookup www.TheSiteThatFailedBefore.com

Chris
0
 

Author Comment

by:bernardb
ID: 34865774
Here's another piece....

I can get to www.blah.org

but not www.blah.org/dev

internally it doesn't work, but externally from outside of our network I can. it's on the same server etc.
0
 

Author Comment

by:bernardb
ID: 34865805
and the error is 'HTTP 404 - File not found
Internet Explorer'
0
 
LVL 70

Expert Comment

by:Chris Dent
ID: 34865806

That takes it out of the hands of DNS.

If you couldn't get to www.blah.org, but could to bob.blah.org we could blame DNS. But if it's a sub-directory under a website DNS is done before you get to the /dev bit.

Chris
0
DevOps Toolchain Recommendations

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

 
LVL 70

Expert Comment

by:Chris Dent
ID: 34865832

> and the error is 'HTTP 404 - File not found ...

Even better, the only thing that can return that is the remote web server. Now you ruled out both DNS and the network layer.

Either the web server is wrong, or we swing back and wonder if you're getting the same answer. Fortunately we can check that:

nslookup www.blah.org
nslookup www.blah.org 8.8.8.8

The first asks your internal DNS server, the second Google's DNS server. Both should return the same thing in almost all cases.

Chris
0
 
LVL 4

Expert Comment

by:evgeny_f31
ID: 34865880
if I put in a static DNS like 4.2.2.2, then I can get to the site
Does it work if you use 4.2.2.2 as dns forwarder address ?
How exactly your network gets the internet - routers, proxy  ?
0
 

Author Comment

by:bernardb
ID: 34866827
Chris-Dent
They return different IP addresses when I tried

nslookup www.blah.org
nslookup www.blah.org 8.8.8.8

The first asks your internal DNS server, the second Google's DNS server. Both should return the same thing in almost all cases.
0
 

Accepted Solution

by:
bernardb earned 0 total points
ID: 34874388
Thanks Everyone.

The issue was we had an A record on our DNS server that pointed to www.blah.org's old internet service provider.

I removed the A record
0
 

Author Closing Comment

by:bernardb
ID: 34904875
Resolved by me, but thanks to all. You Experts are the best.
0

Featured Post

3 Use Cases for Connected Systems

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, testing some more, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us.

Question has a verified solution.

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

Most DNS problems are VERY easily troubleshot and identifiable if you can follow the steps a DNS query takes. I would like to share the step-by-step a DNS query takes from the origin to the destination. _____________________________________________…
I've written instructions for one router type, but this principle may be useful for others of the same brand and even other brands of router. Problem: I had an issue especially with mobile devices that refused to use DNS information supplied via…
This Micro Tutorial hows how you can integrate  Mac OSX to a Windows Active Directory Domain. Apple has made it easy to allow users to bind their macs to a windows domain with relative ease. The following video show how to bind OSX Mavericks to …
Windows 10 is mostly good. However the one thing that annoys me is how many clicks you have to do to dial a VPN connection. You have to go to settings from the start menu, (2 clicks), Network and Internet (1 click), Click VPN (another click) then fi…

920 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

16 Experts available now in Live!

Get 1:1 Help Now