Setting up primary DNS for your internet domain name with Posadis in 5 minutes

This Part III in the award-winning "Setting up X DNS for your X with Posadis in 5 minutes" series, we will set up Posadis as the DNS server for your internet domain name. If you want to know exactly what you're doing, I'd advise you to read the Posadis Manual, but this document is meant to get Posadis to work in about five minutes on a Windows machine (though similar instructions also apply to Linux, FreeBSD, and other operating systems Posadis runs on).

This document will also describe what measures to take to set up Posadis as both a DNS server for your internet domain name and for your local network.

Installing Posadis

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

Now, if you want to use Posadis as a caching DNS server for your internal network as well as as a server for your internet domain name, you'll want to follow the instructions in the "Setting up DNS for your local network with Posadis in 5 minutes" guide, except for the part in which it says you should edit your Posadisrc file. In this document, we're going to edit the Posadisrc as well, albeit in a slightly different way.

So, in any case, click the "Edit Posadisrc" entry in your Posadis Start Menu Folder, after which the Posadis configuration file opens up. Look for a line containing "allow_recursion none" (line 109 in Posadis 0.60.2). If you want to use Posadis for your local network as well, remove the semicolon in front and edit it to match your local network (in the example, "192.168.*" means any IP number of the form 192.168.a.b, so for example if you use 10.0.0.a addresses for your local network, enter 10.0.0.*). If you don't want to use Posadis for your local network, just remove the semicolon in front, after which it should read something like:

Posadis configuration file

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

Posadis running

Setting up internet domain names

This document won't describe how to register a domain name; we'll just assume you've already done that or plan to do it soon anyway.

Allright, now, in the windows of Posadis we have running, we see a message "starting monitoring on C:\Program Files\Posadis 0.60.2\Config\", or something like that. Now, this is the directory we're going to create a zone master file in, which will contain the actual information for our own domain. In this example, we're going to set up the "acdam.net" domain. We're going to create a zone master file named "acdam.net.prm". We do this by going to the configuration directory with the Windows Explorer, and choosing to create a new master file there:

Create new master file

Now, if you disabled the "Hide file extensions for known file types" option of Windows Explorer (which is always 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 "acdam.net.prm", but usually, just enter "acdam.net".

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

New master file

In the "IP number of this DNS server" entry, you will want to enter the internet IP number of this DNS server (duh). For the rest, you can just fill in the fields you want to fill in, after all, it's your domain we're setting up. The "secondary DNS" entry is for another DNS server for the zone; usually you'll want to have more than one, and there are some free services available to do that for you. We'll come back on that later.

This dialog will create a basic zone skeleton, for example:

The master file editor

You can play a bit with this by yourself; in the "Add record" dialogs, context help about the record types is available. This basic zone skeleton is usually enough as a starting point, and it should show you what the zone should contain. Note that domain names in zone master files are displayed relative to the zone root (that is, in the “acdam.net” zone, “ns1” means “ns1.acdam.net”, and “@”, the origin sign, means “acdam.net”). If you need absolute domain names (for domains outside your zone), make sure they have a trailing dot, for example “dns.secondary.com."

Quoting from the Posadis Manual, this is what a zone should at least contain:

The SOA record contains general zone information. If you want more information, double-click on the SOA record, and leave your mouse on one of the text fields to get the scoop on that parameter (for the moment you can leave them use as-is).
The third parameter is the zone serial number. Changing it is a sign to secondary DNS servers that something has changed and that they should re-load the zone. As of Posadis 0.60.3, the Master File Editor automatically increases this number when you save your master file.
NS records, attached to the zone root, list the DNS servers for the zone by their domain names. Each domain name in your zone you use here should also have A records. If you use a third-party secondary DNS service, you'll also want to add their DNS server domain names (for example “dns.secondary.com.”) here as well.
A MX record attached to a domain name points to mail exchange servers for the domain, that is, the server that receives mail for the domain. So if we want to receive mail for “.net”, we will make a MX record for “acdam.net.”. The numeric value is a preference value which says what mail server to try first: mail servers with low priority will be tried first.
A records determine addresses for domain names. You will need A records for domain names you referred to in SOA, MX and NS records (press the “Syntax check” button to see which domains you have forgotten), and you will also want to add them for other domains you intend to use, for example the “www” and “ftp” subdomains and so on.
If you want to define IPv6 addresses for your hosts, you use the AAAA record type rather than, or in addition to, A records.

Now, if you have created the records you need, you can use the DNS query tool (from the Posadis Start Menu folder) to verify that eveything works:

Slaves

Like I said, you will usually want to have multiple DNS servers for your domain in case one stops working. In fact, some registrars will require you to have multiple DNS servers. These secondary DNS servers will load the complete zone from the primary DNS server (which we just set up) using a zone transfer and then start serving queries for it.

Luckily, there are some free (or at least cheap) slave DNS services out there. Twisted4life and secondary.com spring to mind when it comes to free secondary services.

Apart from adding NS records for the slave DNS servers you have, as pointed out above, you will also need to list their IP numbers in the zone configuration (editable by clicking the "Zone configuration" button in the master file editor). For example, if and are slave DNS servers for the domain, we enter the following:

Setting slaves

Third-party slave DNS services will list the IP numbers of their slave DNS servers on their website so that you know how to configure your server.

If you have Posadis 0.60.3 or later, when you save your changes in the Master File Editor, it will automatically increase the zone serial number and send out notifications so that the changes get propagated to slaves directly.

Setting up Posadis as a service

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 operating systems such as Windows 2000 and Windows XP. On Windows 95, 98 and ME, you'll just have to live with the Posadis window currently.

Close Posadis by opening the window and pressing CTRL-C, and choosing "Y" when it asks to close the batch job. Now, choose "Install or remove service" from the Posadis Start Menu entry, and fire up the Windows service 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.

More information

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

Questions about this document can be directed to .