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Resolving a routing issue using a local DNS server (windows network)

Posted on 2004-03-26
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Last Modified: 2010-04-11
I am attempting to set up a DNS server on the following network.

cable modem = pt. of entry
   -> Cisco 831 router
      -> Web server (windows 2003 enterprise)
      -> Web server (windows 2003 enterprise)
      -> switch
           -> 4 client machines

I do not have a domain, all servers are just a member of the workgroup "WorkGroup" I am setting up the DNS server on my LAN because while developing web applications on our LAN our Cisco router refuses to let us view web pages via the WAN external IP address (or if we try a domain name - like (www.asitewemade.com) that points to our WAN IP address).  There are workarounds but they are all fairly ugly

example if we want to browse www.some_site_we_made.com - we can not go "out" through the cisco router then come back in, I think it's referred to as a split-horizon problem.

ANyway I just want a DNS server that says to us on the LAN, "hey I see you attempting to access www.some_site_we_made.com and let's not go out the router, but rahter just stay on our LAN

so instead of trying to resolve www.some_site_we_made.com to our external WAN IP, it routes to our local LAN IP, which works fine when we force it to do that.

PROBLEM / QUESTION - I installed DNS server one one of the servers, and I need to know if it will work without an existing windows domain on our network -

when I point a client machine, behind the router on our little LAN, to the DNS sever I set up (make it the primary and only DNS server in TCP/IP) - it does forward the traffic out ot our ISPs DNS server via the forwarder settings.

How do I tell the DNS server to take, for instance, www.internxchange.com (a site we made and host) and not go out of the router to try and resolve it, but rather to forward it to our production web servers LAN address (192.168.1.71)

I tried to add www.internxchange.com as an entry in a Forward lookup zone I created and tell it to point to 192.168.1.71, but it doesn't it still tried to go out the router and come back in and it causes the "split horizon" problem - in a nutshell we get either a blank web browser screen or it asks us to log into the router (just as if we typed the routers LAN IP address in a web browser window and attemted to adminster control of the router)

HELP PLEASE - thank you very very much
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Question by:oompahii
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by:kabaam
ID: 10692938
you can actually do this without a dns server.
lmhosts file is queried for resolution of name/ips before going to a dns server
an entry like this will work on the clients
www.internxchange.com     192.168.1.71

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by:kabaam
ID: 10692957
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by:oompahii
ID: 10693106
I entered this on my desktop machine in the lmhosts.sam files

www.internxchange.com   192.168.1.71/_clients/internxchange

it still doesn't load, I can manually put   10.10.10.2/_clients/internxchange

into my browser and it finds it,

even if it did work I don't think it will fix my problem...we have an internal / exteranl UBB we use to post solutions to project questions, and it uses hard link (it points to our external WAN IP address when loading threads)

is there a way to tell my PC whenever it sees our externa WAN IP address in a web browser to convert it to our internal lan IP address ?

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Author Comment

by:oompahii
ID: 10693129
also, do you know if DNS will run ok on our network if we don't have any windows doamins setup?

If this is ok to do then at least I know I'm not totally banging my head against the wall
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Author Comment

by:oompahii
ID: 10693131
woops sorry our LAN IP is 10.10.10.x now, was 192.168.1.x before - regardless I'm sure you get the point....
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by:infotrader
ID: 10693277
DNS is a prerequisite for Active Directory domain, BUT Domain isn't a prerequisit for DNS.

LMHOSTS isn't as good as HOSTS file when you want to use it to resolve IP address to name.  Use the HOSTS file instead.  It's under the same directory as your LMHOSTS file.

Finally, once you setup an Internal DNS, make sure it does query forwarding to an External DNS server so it can resolve for your clients any Domain that isn't listed on your local server.  

One last step to verify:  Make sure your clients point their DNS server entry to the local DNS server.

- Info
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by:visioneer
ID: 10693567
The step regarding the query forwarding isn't entirely necessary if the DNS server supports recursion (which the Windows DNS server does by default).

In other words, just installing the Windows NT/2000/2003 DNS Server service and starting it is usually enough to make it work for Internet DNS lookups.  It installs as a cache-only server.

After you install DNS, create a Primary Zone called "asitewemade.com" and make sure it is configured to NOT transfer to any other name servers.  Next, create an A (Host) record for "www" that points to your internal address.  

After that, you need to do the final step as infotrader suggested and make sure all your internal clients are pointing only at your new DNS server for name resolution.  When they query the server for www.asitewemade.com, the server will authoritatively return your internal address.  For all other names, such as www.yahoo.com, it will do a recursive lookup out to the Internet to find the answer, cache the answer, and return the answer to your clients.

I hope this helps.
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Jman8R earned 250 total points
ID: 10693581
You have basically two options here.

As the above post says, use the hosts file. Do not put in the full web path into the hosts file tho.

For example:
10.10.10.2                          www.internxchange.com

Make sure that you leave the localhost entry that is already there alone.

Reboot the machines after adding this entry.


You can also use a DNS server. You would need to configure your ISP's DNS servers as the forwarders as you mention. Then you can add entries ( A host records ) for the domains that you wish. Configure your clients/computers to use your DNS server for name resolution. Restart the computers when these settings have been changed.

Using a DNS server will be a better solution if you will be making regular changes to these domains for several reasons:
  - You only have to make the changes on one computer instead of all computers.
  - You could create a stronger/strickter firewall as DNS quieries only need to come from one PC and not everyone on the network.
  - Computers will not need to be rebooted when changes are made to these entries ( although you may have some issues regarding to cached DNS entries on the computers when making changes. use 'ipconfig /flushdns' to help with this if you are having trouble ).

Disadvantages:
  - The computer hosting the DNS service will need to always be on so that the computers can browse the internet.
  - If there is a problem with the DNS server, computer will not be able to browse the internet.


Hope that this helps!
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Author Comment

by:oompahii
ID: 10706175
OK guys thanks for the input - I am away from the office until later tonight.  I will try your recommendations and awards points accordingly if I get the problem resolved.

Currently I have DNS running with ip address  10.10.10.10 (windows 2003 enterprise server ed.)

I have my ISPs DNS address set as forwarders - but this doesn't seem necessary as DNS has some universal DNS entries automatically applied as forwarders it seems.

I created a FORWARD LOOKUP ZONE and am working in it, in hopes of telling this zone how to handle www.internxchange.com and other sites we host

my client machines only have one DNS entry in TCP/IP which is  10.10.10.10

so I believe I am doing what you guys are telling me - if I am not please correct me

I am getting tripped up on creating an A name for www.internxchange.com though, it seems straight forward enough, but I am not getting it to work.

If you could provide me a step by step algorithm to setting it up and it works for me, I will be much obliged, thank you all for the help thus far...
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by:visioneer
ID: 10706218
It sounds like you're on the right track.

Here's how you create your A record...

Right-click the zone name, select "New Host..."
In the "Name" field, enter: www
Put in the IP address.
Click "Add Host".

Voila!
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by:Jman8R
ID: 10710383
Firstly you will need to create a new "Forward Lookup Zone" for the domain "internxchange.com". You can simply create it as a Standard Primary Zone.

After the zone is created, create a host record for "www" as per the previous post. Make sure that you create this host within the "internxchange.com" zone.
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