Setting Up DNS for Your Local Network With Posadis in 5 Minutes

Setting up DNS for your local network with Posadisin 5 minutesThough the Posadis manual is nice if you want to know what you're doing when setting up Posadis, if you justwant to use Posadis to set up DNS for your local network, then you may not be all that interested in what theDomain Name System really is, you may just want it to work. That's what this document is for: following thisguide you'll be able to set up Posadis on a Windows machine (though similar instructions would also apply forother operating systems such as Linux and FreeBSD) in what should be about five minutes.

Setting up DNS for your local network has a couple of advantages:

DNS lookups will be fasterClients will not need DNS traffic to the outside world anymore, making it easier to set up a firewall.You can assign domain names to machines on your local network, e.g. "thunderbird.localnet".

So, let's start.

Installing Posadis

You can download the latest Posadis from the Posadis download page. Just fetch the latest Posadis exe, at thetime of writing posadis-0.60.2.exe. Install Posadis by means of the well-known "Next"-clicking sequence.

If the computer you're running Posadis on has a direct connection to the internet (that is, it has its own internetIP number), you'll want to make sure Posadis doesn't answer queries from the outside world, only from yourlocal network, as a security measure. To do this, click the "Edit Posadisrc" entry in your Posadis Start MenuFolder, and look for the "listen any" line (line 22 in Posadis 0.60.2). Place a semicolon in front of it, and insert aline "listen 192.168.1.100, 127.0.0.1", supposing 192.168.1.100 is your local network IP number. It should looksomething like this:

Setting up DNS for your local network with Posadis in 5 minutes http://posadis.sourceforge.net/docs/tutorial/cache.html

1 of 7 2013-06-13 22:59

http://posadis.sourceforge.net/docs/tutorial/cache.html

Allright, we're ready to start Posadis now. Click the "Start Posadis" entry in your Posadis Start Menu folder, andPosadis will start running:

Posadis can now already be used to look up internet domain names, as we can verify by starting the DNS querytool from the Posadis start menu group:


2 of 7 2013-06-13 22:59


Setting up domain names for your local network

So, that's kind of neat. But maybe we also want to assign domain names to our local network computers (thesewon't be visible to the internet though). Note that this is not necessary for sharing files and printers withWindows and stuff, but it's kind of neat if you run a web server or a mail server or something on your localnetwork.

Allright, now, in the windows of Posadis we have running, we see a message "starting monitoring onC:\Program Files\Posadis 0.60.2\Config\", or something like that. Now, this is the directory we're going to createa zone master file in, which will contain the address information for our local network. At first we're going todecide to call our computers <name>.localnet, to prevent the names from clashing with existing internet domainnames. "<name>.local", "<name>.home", or something with your name in it will also work.

Now we're going to create a zone master file named <domain>.prm, so in our case, it's called localnet.prm. Wedo this by going to the configuration directory with the Windows Explorer, and choosing to create a new masterfile there:

Now, if you disabled the "Hide file extensions for known file types" option of Windows Explorer (which isalways one of the first things I do after installing Windows, but not many people seem to agree with me on this),you'll want to enter "localnet.prm", but usually, just enter "localnet".


3 of 7 2013-06-13 22:59


Now, double-click on the master file to see the Posadis Master File Editor popping up and showing us thefollowing dialog:

In the "IP number of this DNS server" entry, you will want to enter the IP number of this DNS server (duh). Forthe rest, you can leave it as-is (or fill in other fields if you want to). Now we get to the main screen of theMaster File Editor. What we're going to do is insert address records for the network computers we have (bypressing the Insert toolbar button and then "A - IPv4 address"). In the "Add A record" dialog, you need to enterthe domain name you want to define, and its IP number. The domain name you enter here, is relative to the rootdomain of the data file, in this case "localnet". So to set the address of "thunderbird.localnet" to"192.168.1.100", do something like:

Now, do this for each and every domain name you want to create, and finish by saving the file. Posadis willautomagically re-load the master file once you save it, so we can fire up the DNS query tool again to verify thateveything works:

Setting up Posadis as a service


4 of 7 2013-06-13 22:59


Now, as a finishing tough, we're going to set up Posadis to start as a Windows service once the computer starts,so we don't have this "Start Posadis" window anymore. This will only work on Windows NT-based operatingsystems such as Windows 2000 and Windows XP. On Windows 95, 98 and ME, you'll just have to live with thePosadis window currently.

Close Posadis by opening the window and pressing CTRL-C, and choosing "Y" when it asks to close the batchjob. Now, choose "Install or remove service" from the Posadis Start Menu entry, and fire up the Windowsservice manager (under Windows XP, this is done by choosing "Performance and Maintenance ->Administrative Tools -> Services" in the Control Panel), and we see Posadis is added there:

Posadis is set to start up on boot now, and you can start, stop and restart Posadis from the service manager.

Client PC's

Now, of course, you'll also need to set up client PC's to use Posadis as their DNS server. You can do this byediting the TCP/IP properties of your network card, but how to do this depends on your operating system.Under Windows XP, choose the "Network and Internet connections" item from the Start Menu, and click on"Nework Connections". By right-clicking on your network card, choosing Properties and double-clicking onTCP/IP in the used items list, you enter a dialog in which the DNS server can be entered:


5 of 7 2013-06-13 22:59


By clicking the "Advanced" button, we can even edit the DNS search list by editing the value of the "DNSsuffix for this connection" field:

Now, if we just enter "thunderbird" rather than "thunderbird.localnet" in our internet programs (the DNS query


6 of 7 2013-06-13 22:59


tool doesn't do this though), lookups will also succeed:

Other operating systems, including Windows 9x, also support this functionality.

More information

If you have problems setting up Posadis, a good place to look are the Posadis Forums, and the FrequentlyAsked Questions.

Questions about this document can be directed to [email protected].


7 of 7 2013-06-13 22:59

mailto:[email protected]


Documents

Setting Up DNS for Your Local Network With Posadis in 5 Minutes