We faced a problem with our DNS (link), that made me look deeper into its configuration.

Our server is Microsoft Server 2003 which runs two services FTP and DNS.

You can configure many IPs on a single network card, this is common with web servers running multiple sites. You can view the multiple IPs, in the Advance TCP/IP settings of your network card. Under the IP Settings tab.

For web services, in the IIS configuration you can assign each site an IP, because by default each site runs on the default port 80 (http), so if you want to run multiple sites on the same IP you need to assign different ports not used by other services. So to avoid all that and for end users to access directly through http default port, each site has an independent IP.

For DNS in Microsoft, if you go to the management console, there are some settings to which IP to listen to receive DNS requests and also, which DNS servers to trust to load records from. To know which IP the DNS is actually using, right click the DNS and select Launch nslookup, the IP that appears at the top of the command window is the IP binded to the DNS service.

What I came to notice, it’s the first IP in the IP addresses in the Advance TCP/IP settings.

Solution:

To overcome the problem, I faced in my previous post. I just removed the  IP I wanted the DNS to use and added it again and it appeared on the top. And that solved the problem and I removed the IP used by the FTP from all our primary DNS settings.

In IIS settings, if you go to your FTP site, and see the properties, you’ll see the IP the FTP uses.