Static IP and Domain Name with Lion Server

Public Internet vs. Your Private Network



There is a key boundary that exists at your router or firewall that acts as a gateway for Internet and network traffic.

  • Beyond that line and outside your gateway (router or firewall) is the public world, public DNS, public static and dynamic IP addresses, and your public DNS names for your network.


  • Inside that boundary is your own private network and your own private DNS and static IP which is required by Snow Leopard Serve or Lion Server.




Get a Static IP Address and Domain Name


Make sure to set up a static IP (Internet Protocol) address this is a unique address on your local network. Having this static IP will allow port forwarding services from the router to the computer it is hosted on.

In most cases your Mac will have a dynamic IP address. Dynamic addresses change periodically, usually when you restart your computer, while static IP addresses always stay the same.


Public IP numbers


In most cases you will have a public IP address, given to you by your Internet Service Provider (ISP). This is an IP that is unique to you and the entire worldwide Internet.

For example we will give our fictional business or home the public IP address of:


In most cases your Internet router will have this public address preassigned to it, but your router has to manage the many devices in your home or business network. This is where a private IP address is important. The private IP address allows multiple devices under one public IP address to connect to the Internet and not interfere with each other. With a private IP, your router acts as a switch between the public Internet and your private network. This idea is similar to an apartment complex; it has one public address on the street and designated numbered apartments inside.



Private IP numbers


There are a range of IP addresses that are reserved for private networks and are never given out for public use. The private IP addresses usually start with 192.168, and your router in most cases will be set to or by default. With a private IP address, your router will designate unique addresses within the network range to all Internet connected devices on your network. Your router, having the public Internet address will also use a process called network address translation (NAT). The NAT process will determine which bits of information going to and from the Internet are supposed to link to the specific devices with their own private IP addresses inside your network.

So your network will have a public IP address (in this example it is, and your router will also have a private address (for this example). In this configuration the router will designate unique private addresses to your Macs or Mac devices (ie. – where the last digit, 8, is the next available address for a particular device, since the router knows that 7 other devices (including the router) work inside your network and will also have IP addresses.



VPN: The same IP addresses from two networks will cause conflicts.



If you are setting up a Virtual Private network connection to your server then it will be necessary to change the IP address range your router assigns. This is because a VPN provides a connection that connects a device directly to your own network from outside the network. Most routers use either the 192.168.0.XXX or 192.168.1.XXX IP address range. Using a private IP address for a device in the remote location that has the same IP address on another device in the network location will create communication conflicts.



The router will try to send data to another device from within the network, instead of connecting to your own network over the Internet.

So if you think you will be using VPN, then set your router to use a range like 192.168.99.XXX, so long as that third number is not 0, 1 or 2 you should be good to go. If you do not set up a new private IP address range, keep in mind that your connected devices will need to be updated with the changed IP address of your router to re-establish their internet connection.



Domain names


There is one last important step left if you want to set up a public server:

  • Getting a domain name.

You will need to purchase a unique domain name and link it to your public IP address.

It is pretty obvious why domain names are used on the Internet. IP numbers are linked to domain names for public services like websites because it is difficult to remember long strings of numbers. It is much easier to remember than

There are two types of public IP addresses that will affect what you do when setting up a domain name system.

Static and dynamic IP addresses



Most businesses get static IP addresses from their service providers included in a business package. When you purchase a domain name you can link it to your public IP address so that setting up services can use a name like instead of

If you want to find out your current IP address you can go to this site, it is a free service.

Something to remember is that most Internet Service Providers give you a dynamic IP address. A dynamic IP address is an IP address that is designated by a DHCP server, instead of one that was manually configured. A dynamic IP address works by assigning an IP address from a pool of available addresses each time you log on to the ISP or reset your router. Most routers are usually always connected to the Internet, so this means your dynamic IP address in most cases, only changes when you reboot your router or the ISP makes network changes.


Linking a Domain name to your static IP address



If you have a static IP address, you can register your domain name with a domain name provider and know that the link is not going to change. If you just want to own a domain, you will not need to pay for web space hosting with a provider, however make sure the provider lets you control where your purchased domain points to.


With a registered domain name,, you will want the domain to point to your public IP address. The registered domain name will provide you with a web based control panel where you can change something called: “A records” (address records). A records, are address records that communicate to the Internet’s domain name servers (DNS) to send any request for that specific domain name to your public IP address. In a nutshell they point domains or subdomains to a specific, assigned IP address.

Here is an example of a domain system for a random provider (courtesy of: louishen). There will be a domain section in the control panel and there should be various A records set to point to your public IP address.




The unique server domain name will allow you to control which services will be handled by Lion Server and which services, like mail or web hosting, will be managed by a service provider, or perhaps a separate computer in your network.


Changing domain name A records takes a bit of time, usually around 24-48 hours.


After completing the previously discussed steps you will have a working domain name on the Internet. The domain name servers will know how to direct any traffic to your domain when devices outside of your network want to communicate with your server inside your home or business network.

There is also the option of creating a public server that could be registered for example as, and this would be linked to a public IP address.


Linking a Domain Name to a Dynamic IP address


If you decided to use a dynamic address, you have a couple options:

  • Monitor your IP address and update it manually whenever it changes
  • Use a dynamic DNS service such as DynDNS.
  • The manual method is not usually the preferred method. This is because you may not know when your dynamic IP address changes. Also, your domain would remain offline for however long it takes to update your address records (A records).

A dynamic DNS service provider will be able to register a domain for your network and have it link to your dynamic public IP address on a moment-to-moment basis.

There are a couple ways to keep track of your dynamic IP address and make sure their servers are appropriately updated. You can use your network router to keep your IP address updated. Most routers these days support this function.



Or if your router does not have this option then the second option is to use a dynamic DNS service provider.

The next step is to configure your router to enable Lion Server’s many services between your network server(s)and the Internet.