Have you ever wondered how you could access your external hostnames, internal to your network connected via wifi, mobile devices or just plain old desktops? Today we found out we needed to. Our mobile devices require the use of external hostnames to sync data against. And it’s nice being able to use our external hostname for Outlook Web Access, and debugging internally.

For example:

  • Billy wants to visit http://www.mycompanyname.com
  • Billy can’t because that particular site is hosted off the external IP of the network he’s on. Gosh, what to do?
  • Billy Reads the Howto Setup SPLIT-SPLIT DNS with SBS 2003 DNS Server below
  • Billy can now visit http://www.mycompanyname.com because it’s mapped to the internal ip of or whatever your networking scheme is.
  • Billy is now happy.

Off we went to Google, to try and find out what we needed; DNS Redirection? No, IP Port Redirection? No, Redirect External IP to Local IP, No. Tiresom it was, searching for this.

Then we decided to try and jump right in to figuring it out. First, we tried doing it at the router level, but none of us are IOS guru’s so this quickly became out of the question. Next we tried running a secondary DNS server on the SBS2K3 Server, and transferring the domain from our live server at the Datacenter in Seattle. This also didn’t work because once the domain was transferred into our secondary DNS on the Windows 2003 Server we weren’t able to edit any of the records. Pitty.

So, on we were to IRC. Ahhh, IRC. Not too many people use it anymore, but usually really cool people are available to help out. After asking in a couple channels we figured out that what we needed to do was set up something called Split-Split DNS. Basically all this is, is the method of running two DNS Servers. One inside your network, and one external to your network. Here’s a Microsoft Article on the subject of Enterprise DNS Design which involves Split-Split DNS. This allows for internal hosts behind NAT networks to see external hostnames as if they are on the internal network.

With a bit more searching we came across this excellent post by Ginger Lime. Using their instructions we have created a simple howto for doing the same thing on your internal domain.

With our little howto, you’ll be able to get this done quickly and easily on your internal windows sbs 2003 domain name server. Please readon for the howto.

First, we’ll have to open the DNS control panel. This is in the main server management console, under the computer management box. Here’s a screenshot. Make sure you enter into the Forward Lookup Zones box.

Now, right click on “Forward Lookup Zones” and click on “Add New Zone”. Like This.

Now you’ll be presented with the New Zone Wizard window. Click Next.

Now, Select a primary Zone for this tutorial.

Disable the storage of the information in Active Directory. Click Next.

Now type in your domain name that you want to resolve internally. Some common ones might be dev.yourdomain.com or www.yourdomain.com or similar. Click Next.

This window will be automatically filled out for you. Just click Next.

Now, make sure you don’t allow dynamic updates. This record is something you should be manually updating only. Click Next.

Your new zone is complete. Click Finish.

Now, Right Click your new zone (external.hostname.com), and select to “New Host (A)”. Let go of your mouse button now. 🙂

Now, add your internal IP address to the host, but leave the Name blank. Like this. Also leave the PTR record one un-checked since we don’t need it. Click Add Host.

You should see a message like this pop up.

Click on the Done button to leave this window.

Now you should see a blank host, with the internal IP address you specified during the last section of this tutorial.

Now you’re finished setting up a SPLIT-SPLIT DNS server using SBS2k3.

Go over to a different computer on your network that uses the Windows 2003 SBS Server as it’s DNS Controller, and try a nslookup or ping against the external hostname you’ve just added. If you get ping returns you’re good to go.


Comment by Ben Mason on 2008-11-26 07:46:45 -0500

Thanks very much for this, very helpful 🙂

Comment by Matt G on 2008-11-26 10:29:30 -0500

Hey Ben,

No problem. Sorry the screenshots are missing – I have no idea where they went, and I can’t find my backups 🙁

Glad you got it working though, it’s very handy 🙂


Comment by ChipConnJohn on 2009-06-23 12:12:03 -0500

Awesome! No need for the screenshots. Once you see it step by step it makes perfect sense. Thanks much!

Comment by Dennis on 2010-08-31 02:35:54 -0500

Thanks for this, just what I was looking for. I am wondering though, do I need to do this for all my domains? We run a multitude of web server instances, such as http://www.xxx.fi , http://www.xxx.com, http://www.xxx.co.uk and such. Do I need to make a new zone for each of these or can I make a single zone and keep using the “New Host (A)” to map to each url to the internal IP?

Comment by Mikael Ljung on 2011-04-20 16:42:20 -0500

Hi man,
I was really happy to come across your site with split dns. But, all the pictures are removed from the site.
Please, put them back. Otherwise nobody will understand anything from your tutorial

Comment by Matt G on 2011-05-13 01:14:29 -0500

Hey Mikael,

I can’t find the pictures, they seem to have been lost in an upgrade. I will keep looking though!

Comment by Jack on 2011-07-08 12:00:49 -0500

This is EXACTLY what I was looking for. Thanks so much!