The Scenario:

I am creating a Network for 8 Windows 7 Workstations running in a Student Laboratory. They are supposed to browse the internet, but not to be reached from outside their intranet. To achieve this, i run an Ubuntu 14.04 server with 2 NIC's. One NIC (em1) is connected to our department VLAN, i.e. the internet. I'm routing the Workstation-intranet to NIC em2 via IPV4 forwarding over iptables' MASQUERADE feature.


departments VLAN
Ubuntu server / iptables
|  |  |  |  |
W  W  W  W  W ...

After some hiccups, this works fine, see my other post for the full picture (and some of my configurations):


The Ubuntu server is the only machine with a valid IP from the VLAN and needs to use the departments VLAN's DNS servers, or it can't reach the internet. As i found out via my other post, all the clients need to use our departments DNS servers as well, as their packages run via the Ubuntu router and are masqueraded as packages from it.

The Problem:

Now, i want to deploy an Microsoft Active Domain Controller via Samba. But: I need to run my own DNS in the intranet to use all the cool features from a Microsoft Network. The hostnames need to be resolved for Virtual Disks, Log-In, group policies etc.. If i do so, however, the machines will not be able to use the outside / departments DNS anymore and therefore can't request packages from the internet.

How to solve this?

Can i use the departments DNS to resolve my hostnames in the intranet? (Probably not, right?)

Is there a way, that my workstations get their name from my DNS, but request internet packages from the outside DNS to be reached under the same IP?

Is this, why there are usually two fields for DNS servers?

Can i "re-route" the outside DNS parallel to my own DNS into the intranet?


Install your Windows domain as usual and point the clients to the Windows domain's DNS server, and set the department's DNS servers as forwarders in the Windows DNS server. The manual to do that: http://technet.microsoft.com/en-us/library/cc754941.aspx

  • I will try this next week when i am back at work. Thanks for providing that link and giving a "windows" answer. – zerweck Oct 24 '14 at 16:06

Install your own DNS server on the Ubuntu server. The Ubuntu Server Guide has a chapter on DNS.

Configure your DNS server as authoritative for your Active Directory Domain. Configure the department's DNS servers as forwarders.

  • I will try this next week when i am back at work. Thanks for providing that link and giving the "ubuntu" answer. – zerweck Oct 24 '14 at 16:07

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