IP Considerations

 Every device on a network has a unique number within that network to identify it, known as its IP address. These numbers consist of four sets of digits and take the form nnn.nnn.nnn.nnn. Nearly all of the possible numbers are allocated to the internet for websites and other purposes and are known as public IP addresses. However, a small selection are available for internal or local area networks; these are known as private IP addresses and are invisible to the outside world. As these IP addresses are private they can safely be used by anyone and the exact same numbers are used millions of times over. The three sequences which are available for private use are: 

10.0.0.0 to 10.255.255.255 

172.16.0.0 to 172.31.255.255 

192.168.0.0 to 192.168.255.255 

Most equipment intended for use in small businesses and homes tends to be preset to use the 192.168.nnn.nnn numbering scheme; for instance, internet routers hubs commonly have an address of 192.168.1.1 or 192.168.1.254 depending on brand. Although these addresses can be changed, there is rarely any need to and it is best not to do so unless one has a good understanding of the topic. Essentials seems to make the assumption that a 192.168.nnn.nnn scheme or similar is being used although this is not an absolute.

Devices such as computers and printers do not come with an IP address already allocated; instead, they have to be configured with a suitable address. There are two ways of doing so - you can use static IP addresses or dynamic IP addresses. 

With static IP addresses, it is necessary to visit each device and individually configure it. For instance, you might set the first PC to be 192.168.1.101, the second to be 192.168.1.102, the third to be 192.168.1.103 and so on. You have to be careful to keep track of everything and above all make sure that there are no duplicates. If this sounds like hard work then that’s because it is – you might get away with it if there are only a handful of computers but beyond that it rapidly becomes unworkable.

With dynamic IP addresses, the numbers are assigned automatically by a DHCP (Dynamic Host Configuration Protocol) server and it keeps track of everything. This is not usually a physical server like a file server, rather it is a piece of software. Most all-in-one routers of the sort used in small businesses and homes have DHCP server software built-in. If Essentials detects one of these during theinstallation it will use it. However, if it does not it can provide its own DHCP service, although this has to be separately configured.

Regardless of whether the IP addresses come from a router or are supplied by Essentials itself, it is a good idea to have a scheme to follow. As mentioned above, routers are commonly set to numbers such as 192.168.1.1 or 192.168.1.254. The server should be set to an adjacent address. Printers and any specialised devices should be close by. The numbers allocated for computers should be a contiguous block of numbers elsewhere. So, for instance, a typical setup might be as follows: