Example: working with a class c subnet – Netopia Router PN Series User Manual
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B-8
Reference Guide
5.
Determine the host addresses
Finally, combine your subnet numbers with your host numbers to
determine the actual IP addresses you may use for your 25 hosts.
The first three bytes of the address will always be 199.14.17, as
assigned to you by InterNIC. The final byte will be the sum of the
subnet number and the host number. The following table shows the
ranges of IP addresses you can choose from when you configure
each host.
Example: Working with a Class C subnet
Suppose that your organization has a site with only 10 hosts, and
no plans to add any new hosts. You don’t need a full Class C
address for this site. Many ISPs offer Internet access with only a
portion of a full Internet address.
For example, you may obtain the Class C address 199.14.17.48,
with the mask 255.255.255.240. From the previous example, you
can see that this gives you 14 host addresses to distribute to the
hosts at your site. In effect, your existing network of 10 hosts is a
subnet of the ISP’s network. Since the Class C address has already
been reduced to subnets, you cannot further subnet your network
without the risk of creating network routing problems (since you
Subnet
location
Subnet
number
Smallest
host
number
Largest
host
number
Smallest
combined
total
Largest
combined
total
IP address range
3rd floor
32
1
30
33
62
199.14.17.33 to
199.14.17.62
4th floor
64
1
30
65
94
199.14.17.65 to
199.14.17.94
5th floor
96
1
30
97
126
199.14.17.97 to
199.14.17.126