Ask Me Help Desk - DNS Query Query. A Query about DNS Queries...

I am a software developer, I don’t know much about networks. I have a working network but with one weird (well to me it’s weird) problem. If you can offer any insight I’ll be very grateful!



That’s my network… well a simple diagram anyway. The only thing important I left out was this…. On the Windows 2000 Server, which is the Primary Domain Controller and DNS server… there are two addresses in the DNS forwarding for the domain MyCompanyName.com… they point to the DNS servers of my ISP… they are real world addresses… I understand DNS enough to know my Server needs to forward on any queries it can’t resolve.

I am trying to figure out why my company is having severe problems browsing its own Internet site… yet is able to surf the web whilst streaming iTunes and browsing Google Earth concurrently quite happily (i.e. the network seems to perform very well indeed otherwise!)

I installed the Windows 2000 Server, creating a domain and naming it after my company… .it seemed the right thing to do according to the Windows 2000 domain set up process, they had an example name for the domain (I think it was Microsoft.com)… so I called it “MyCompanyName.com”…. In fact I think I tried to call the domain just “MyCompanyName” but the set up forced me to put a ‘dot’ something… so I went with the example and put .com after my company name.

I am wondering if this is the problem… my internal domain which all my workstations live on is called MyCompany.com…. And I am trying to browse to http://www.mycompany.com.au (which is hosted externally…. We definitely don’t have the capacity to host our own web server!! )

So I was thinking the DNS lookup process then goes nuts trying to find the outside http://www.mycompany.com.au server when my internal domain is called mycompany.com… is there any truth to this? The reality is that the workstations ARE resolving the name via DNS because the page loads…. But failed images and about a minute or so to load a simple page with a few images… sometimes stylesheets don’t load etc. etc. it’s NOT the server our website is hosted on… I literally walk 200 metres down the road to an internet café and test the website from there (sometimes I have to because I get so frustrated trying to load the pages from my network…. Even though I can browse any other website. Same behaviour from all workstations / laptops in network! )

I thought I would investigate / test what I could in case I found something… I tried:

i. Putting an entry in a workstations HOST file for http://www.mycompany.com.au. As a developer we have to do this all the time to control local web servers…. So I figured if the problem was DNS then the workstation would all of a sudden be able to happily connect to my company’s external website properly…. Nope… same performance…. (I did a ipconfig /flushdns at the command prompt before testing too)

ii. Looking into renaming my Domain…. Hmmm… Windows 2000 domain rename needs a BDC with Win NT etc. etc…. Man, I gave up on that, I’d rather re-install Windows 2000 Server and go through the process of re-building!

Do I need to put a special forward or reverse entry lookup thingy in DNS?

Is there such a thing as ‘slow’ DNS in a network like mine?

Do requests for resources like images from Internet Explorer end up in multiple DNS queries?? (Does DNS happen on a packet level?? Argghh… why is this so complicated! WoooF!) …

…or am I barking up the wrong tree?

Your network diagram looks fine to me. I think the problem you have is that your internal domain name is the same as an existing internet domain name. Normally you should set your internal domain with the .local extension, this avoids the problem you are seeing now.

As Stu has already mentioned it sounds like a name conflict.

What result do you get when you try to connect using just the IP address ?

Thanks heaps for getting back!

So is there then a simple way I can rebuild a Domain in Windows 2000... I know it's not possible for me to rename... but can I delete and re-install a domain without having to rebuild the server from scratch?

I know there is a way to setup some zone forwarding or somehting like that to solve the problem... but they're just buzz words to me at the moment.

Sorry CurlyBen... I didn't answer your question...

What result do you get when you try to connect using just the IP address ?

Well... unfortunately the server my site is hosted on has other sites on there too... they use host header separation to achieve this, putting your IP into the web browser is not enough... it has to pass the actual name too... I don't understand this layer (does each packet carry the IP address AND name at the TCP layer! )

Have you tried adding a new zone for your company's web site ?

After rereading your question I must admit to being a little confused by the setup.

The domain DNS seems fine, but then to have problems accessing your externally hosted company site seems very odd indeed.

Can your company's site be accessed fine from outside of your WAN, if you are getting the same issues then its down to your host and NOT your own setup ?

Hi CurlyBen... yeah, it's kind of doing my head in because it doesn't seem to make sense.

But half the problem is that I am not able to confidently say one way or the other if it's my network... do you think the following is a 'black and white' test:

- My web host's setup an alternate real world name for our server... it's nothing like the www.MyCompany.com.au... it's an ugly looking URL with machine names and numbers.

---> Ping this new server... I get the same address as the www.MyCompany.com.au server... great!

---> Flush my DNS... try browsing to this new real world site... same performance!

Do you think that test alone is enough for me to say for sure "There is NO way it could POSSIBLY be DSN clashes on my network" ?

By the way... I did this test on my workstation... maybe should try on server too. Will report if anything different.

May be worth running a traceroute to your site to see if it is your host, but the more you are adding the more I think it is their problem !

If you don't mind pm'ing me your company's url I'll have a look from here.

Quote:

Originally Posted by __Tigger__

Sorry CurlyBen... I didn't answer your question....

What result do you get when you try to connect using just the IP address ?

Well... unfortunately the server my site is hosted on has other sites on there too... they use host header seperation to acheive this, putting your IP into the web browser is not enough.... it has to pass the actual name too... I don't understand this layer (does each packet carry the IP address AND name at the TCP layer!?)

What happens if you take one of your workstations, disable it's DNS client, and manually define the hostname of the server in the workstation's local hosts file?

Thanks heaps for all the support... I have tried:

- Going into the TCP/IP settings for a workstation and removing the DNS server (there is now NO DNS servers for the workstation!! )

- I tested the workstation now has no DNS... can't get to anything... looking good, no DNS at all

- I added an entry for my companies website into the workstation HOST file

- Same behavior... I can get to the Companies website but same issue loading.

Is this then enough for me to say "IT'S NOT MEEEEE!!!!" to my Web Host? Does this test guarantee that there are no DNS issues causing the site to load slowly? We've removed DNS from the picture here right?

Just to let you know (if you're still following) that I have a Network admin from IT&T coming in tomorrow... he reckons it's Routing issues and is nothing to do with DNS.

I will post the final fix to this situation tomorrow afternoon, thanks for all your help so far.

I'd certainly be interested to see the fix. As you've said, if it does the same thing with a different domain name, this suggests it's not a problem with DNS.

That would certainly make some sense.
Also I would maybe look at either getting a different web host or getting them to give you a proper static IP address for your site.