
266
Appendix G IP subnetting
NN47922-501
192.168.1.0 with mask 255.255.255.128 is the subnet itself, and 192.168.1.127
with mask 255.255.255.128 is the directed broadcast address for the first subnet.
Therefore, the lowest IP address that can be assigned to an actual host for the first
subnet is 192.168.1.1 and the highest is 192.168.1.126. Similarly the host ID
range for the second subnet is 192.168.1.129 to 192.168.1.254.
Example: four subnets
The above example illustrated using a 25-bit subnet mask to divide a class C
address space into two subnets. Similarly to divide a class C address into four
subnets, you need to borrow two host ID bits to give four possible combinations
of 00, 01, 10 and 11. The subnet mask is 26 bits
(11111111.11111111.11111111.
11
000000) or 255.255.255.192. Each subnet
contains 6 host ID bits, giving 2
6
-2 or 62 hosts for each subnet (all 0s is the subnet
itself, all 1s is the broadcast address on the subnet).
Table 62
Subnet 1
Network number
Last octet bit value
IP Address
192.168.1.
0
IP Address (Binary)
11000000.10101000.00000001.
00
000000
Subnet Mask (Binary)
11111111.11111111.11111111.
11
000000
Subnet Address: 192.168.1.0
Lowest Host ID: 192.168.1.1
Broadcast Address: 192.168.1.63
Highest Host ID: 192.168.1.62
Table 63
Subnet 2
Network number
Last octet bit value
IP Address
192.168.1.
64
IP Address (Binary)
11000000.10101000.00000001.
01
000000
Subnet Mask (Binary)
11111111.11111111.11111111.
11
000000
Subnet Address: 192.168.1.64
Lowest Host ID: 192.168.1.65
Broadcast Address:
192.168.1.127
Highest Host ID: 192.168.1.126
Summary of Contents for 222
Page 14: ...14 Contents NN47922 501 ...
Page 24: ...24 Tables NN47922 501 ...
Page 30: ...30 Preface NN47922 501 ...
Page 46: ...46 Chapter 2 Introducing the SMT NN47922 501 SMT menus at a glance Figure 6 SMT overview ...
Page 70: ...70 Chapter 3 WAN and Dial Backup Setup NN47922 501 ...
Page 78: ...78 Chapter 4 LAN setup NN47922 501 ...
Page 100: ...100 Chapter 6 Remote Node setup NN47922 501 ...
Page 104: ...104 Chapter 7 IP Static Route Setup NN47922 501 ...
Page 132: ...132 Chapter 9 Network Address Translation NAT NN47922 501 ...
Page 154: ...154 Chapter 11 Filter configuration NN47922 501 ...
Page 158: ...158 Chapter 12 SNMP Configuration NN47922 501 ...
Page 198: ...198 Chapter 15 Firmware and configuration file maintenance NN47922 501 ...
Page 212: ...212 Chapter 17 Remote Management NN47922 501 ...
Page 232: ...232 Appendix B Triangle Route NN47922 501 ...
Page 252: ...252 Appendix D PPPoE NN47922 501 ...
Page 260: ...260 Appendix F Hardware specifications NN47922 501 ...
Page 270: ...270 Appendix G IP subnetting NN47922 501 ...
Page 308: ...308 Appendix H Command Interpreter NN47922 501 ...
Page 312: ...312 Appendix I NetBIOS filter commands NN47922 501 ...
Page 336: ...336 Appendix L Brute force password guessing protection NN47922 501 ...