Setup guide

Dedicated Micros Page 123
It is possible to set a range of IP address within the Firewall that will have access to the Digital
Sprite 2. The following details how the address range and subsequent subnet is calculated and
can be used in conjunction with the Configuration section of this manual.
IP Address and Subnet Masks
An IP address is a 32 bit address that is read by the network devices (switches, hubs, routers) in
a binary format, however to make life simpler for Network Administrator, IP addresses are
displayed in a decimal format.
The same applies to subnet masks, these to are 32 bit addresses and are identified by the
network devices in binary format, but for written in a decimal format.
The 32 bits are grouped in to four 8 bits (an Octet) to give us the IP address format we are used
to:
The binary format of the IP address uses 1’s and 0’s and within an octet it is possible to identify
256 decimal numbers from 0 to 255.
An IP address along with its subnet mask is made up of two parts; Network ID and Host ID. If
we use our example IP address, 192.168.3.1 we can see the network ID and the host ID;
Wherever the subnet gives a value of 255 (all 1’s) it ‘masks’ out the IP address octet and
therefore represent the Network part of the overall IP address. Hence the reason the above
example takes the first three octets as the network ID and the last octet as the host ID.
Appendix E – IP Address Range and Subnets
Binary Format Decimal Equivalent
11000000.10101000.00000011.00000001 192.168.3.1
11111111.11111111.11111111.00000000 255.255.255.0
128 64 32 16 8 4 2 1 Decimal
1 1 1 1 1 1 1 1 255
0 0 0 0 0 0 0 0 0
IP Address Network ID Host ID
192.168.3.1 192.168.3 .1
255.255.255.0 255.255.255 .0