Domain Name Services

From Nitix Knowledgebase

What is DNS?

DNS is the protocol used to convert internet domain names into IP addresses. If DNS is configured, users can access information on the local network and the internet using domain names instead of specific IP addresses.

Configuring DNS services can be complicated because it often requires dealing with outside organizations called Domain Registrars. If you are uncertain about issues related to DNS, ask your ISP to help you.

DNS Services

Nitix runs two different kinds of DNS services:

• DNS Lookup and Caching Server - This server converts domain names (such www.yahoo.com) into IP addresses and then sends the IP addresses to your browser. Nitix runs the DNS lookup and caching server on your local network and blocks connections to the lookup server from the internet. There are no special options to configure the DNS lookup and caching server.
• DNS Publishing Server - This server adds names for your own network (such as www.example.com) into the global DNS system so that people can find your IP address to access your website or to send you email. The DNS Publishing Server and how it can be configured is explained in the rest of this chapter.

Configuring Public DNS

1. Select Local from the Network Setup menu on the left side of any WebConfig screen. The Local Network Options screen will be displayed, with the DNS line as follows:



2. The default DNS server setting is "No", meaning that you are not publishing any DNS entries.
   • This option only controls the DNS publishing server and how people outside your local network communicate with it. The DNS publishing server is always active for computers on your local network.
   • If you want to provides services (such as email) to the outside world, you need to enable the DNS server.
   • To do so, select "Yes" or "Dynamic". Your choice depends on some relatively complex issues involved in domain name registration. We will try to explain some of these issues in the following sections.
3. Click Save Changes when you have selected the appropriate DNS setting.

How the DNS System Works

DNS Hierarchy

The internet DNS server network is arranged as a hierarchy in which a single ‘root’ domain, sometimes called dot (‘.’), links to the set of top-level domains (such as .com and .org). In turn, each of the top-level domains contains a link to each of the second-level domains (such as net-itech.com and mydomain.org). Third- and fourth-level domains are less common and are used in large organizations like universities.

You will most likely publish a second-level domain name such as example.com. When you do that, your DNS server (if enabled) automatically publishes the names inside example.com, such as www.example.com and mail.example.com .

Domain Registrars

However, there is still a part that must be done manually: in this example, you have to create a link on the .com server to ask your second-level domain to be referred to your Nitix-powered server’s IP address. To do this, you need to visit a Domain Registrar (such as www.easydns.com or www.opensrs.org) to make sure that your domain name is not already being used by someone else and to give them the outside IP address of your Nitix-powered server.

In order to register a domain name, your Nitix-powered server must have a static IP address. Most ISPs provide this service for an additional fee. DDNS can be used in place of a static IP address. Refer to Dynamic DNS in this chapter for more information.

After you enable your Public DNS Server and register with a Domain Registrar, people should be able to look up the IP address associated with your domain name. To test this:

1. Click WWW from the Server Setup menu.
2. Select "Yes" in the Enable Web Server field.
3. Ask someone outside the local network if they can view your domain.

Dynamic DNS

Dynamic DNS is a Nitix feature that allows you to publish DNS entries and provide internet services even if you have a dynamic IP address (as opposed to a static IP address).

When you register your domain with a registrar, you give them the address of the primary server and backup server owned by Net Integration Technologies (which already have static IP addresses). When your Nitix-powered server connects to the internet, it automatically informs the Net Integration Technologies servers about your current IP address and asks them to publish your up-to-date DNS information.

You need to provide a Domain Registrar with the following DNS server addresses:

1. dyndns1.ivivanet.com 209.5.34.82
2. dyndns2.ivivanet.com 207.176.197.14
3. dyndns3.ivivanet.com 194.124.152.28

All you need to do then is set your Public DNS Server to "Dynamic". Nitix does the rest.

Manually Creating DNS Entries

Based on the servers you have enabled, Nitix automatically decides which DNS names to publish. For example, if your domain name is example.com, and the Enable Web Server option is set to "Yes" (not "Trusted Hosts Only"), then Nitix automatically publishes the DNS name www.example.com as a pointer to your web server. Similarly, if you enable the SMTP email delivery server, it publishes the name mail.example.com.

Although Nitix publishes names automatically, you may want to occasionally add extra names to your DNS server. You may also want to add an entry that allows people to access your site without typing www. before the address.

Changing DNS information at a registrar (i.e. Network Solutions) can often take 24 - 72 hours to replicate through the DNS backbone.

Types of DNS Entries

You can create four kinds of DNS entries:

• A (address) - Creates an entry for converting a name (such as www.example.com) to an IP address (such as 111.22.33.44). This is the most common type of entry.
• NS (copy from nameserver) - Allows you to mirror someone else’s DNS server. Every DNS server should have a backup server with an additional copy of the data. When you register a domain name, the registrar generally asks for a primary and a secondary server. If someone asks you to act as their secondary DNS server, you can add their domain name and primary server's IP address as an NS entry.
• MX (mail exchanger) - Occasionally, you may want to publish a web server and a mail server with the same name but different IP addresses. For example, you might want people to reach you by email when they send to user@example.com, but you might want the example.com web server to point to a different address. To do that, you would add Address records for </tt>example.com</tt> and www.example.com pointing to your web server, and then you would add an MX entry for example.com pointing to your mail server. You do not need to create a separate MX entry if it will point to the same address as the Address record.
• DR (Dynamic Redirect) - Dynamic redirection can be used to circumvent blocked HTTP (Web) ports. Any Web requests directed to the address entered as "Name" will be automatically redirected by a Dynamic DNS server to port 4201 on the site entered as "Value". This will be almost transparent for clients, who will only notice that the hostname and port have changed slightly.

Creating a DNS Entry

1. Select DNS from the Server Setup menu. The DNS List screen will be displayed:

   

   • To list, create or edit your private DNS entries, click Private Entries.
   • Private DNS entries are available only to the internal network and include hostnames of all the computers the Nitix-powered server can find on the local network.
   • Public DNS entries include the mail exchange (MX) record and entries for the un-trusted (external) network interface. Virtual Web server DNS records will also go on the public DNS list. Most of the listings, both public and private, are automatically set up by Nitix.
2. Click Add DNS. The DNS Add screen will be displayed:



3. Enter a name for the entry.
4. Select the entry type.
5. Enter the target IP address in the Value field.
6. Click Save Changes.

Editing an Existing DNS Entry

1. Select DNS from the Server Setup menu. The DNS List screen will be displayed.
2. To edit your private DNS entries, click Private Entries.
3. Click on the entry’s edit action button. The DNS Edit screen will be displayed:



4. Make the appropriate changes and click Save Changes.

Similar Articles