Appendix C IP Addresses and Subnetting
ZyWALL 2 Plus User’s Guide
649
Figure 463
Subnetting Example: After Subnetting
In a 25-bit subnet the host ID has 7 bits, so each sub-network has a maximum of 2
7
– 2 or 126
possible hosts (a host ID of all zeroes is the subnet’s address itself, all ones is the subnet’s
broadcast address).
192.168.1.0 with mask 255.255.255.128 is subnet
A
itself, and 192.168.1.127 with mask
255.255.255.128 is its broadcast address. Therefore, the lowest IP address that can be assigned
to an actual host for subnet
A
is 192.168.1.1 and the highest is 192.168.1.126.
Similarly, the host ID range for subnet
B
is 192.168.1.129 to 192.168.1.254.
Example: Four Subnets
The previous example illustrated using a 25-bit subnet mask to divide a 24-bit address into two
subnets. Similarly, to divide a 24-bit address into four subnets, you need to “borrow” two host
ID bits to give four possible combinations (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 (a host ID of all
zeroes is the subnet itself, all ones is the subnet’s broadcast address).
Table 231
Subnet 1
IP/SUBNET MASK
NETWORK NUMBER
LAST OCTET BIT
VALUE
IP Address (Decimal)
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
Содержание ADSL 2+ Security Gateway
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Страница 88: ...Chapter 3 Wizard Setup ZyWALL 2 Plus User s Guide 88 ...
Страница 131: ...131 PART II Network LAN Screens 133 Bridge Screens 145 WAN Screens 151 DMZ Screens 171 Wireless LAN 181 ...
Страница 132: ...132 ...
Страница 144: ...Chapter 6 LAN Screens ZyWALL 2 Plus User s Guide 144 ...
Страница 180: ...Chapter 9 DMZ Screens ZyWALL 2 Plus User s Guide 180 ...
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Страница 209: ...Chapter 11 Firewall ZyWALL 2 Plus User s Guide 209 Figure 138 SECURITY FIREWALL Rule Summary Edit ...
Страница 221: ...Chapter 11 Firewall ZyWALL 2 Plus User s Guide 221 Figure 149 My Service Firewall Rule Example Rule Summary Completed ...
Страница 222: ...Chapter 11 Firewall ZyWALL 2 Plus User s Guide 222 ...
Страница 252: ...Chapter 13 Content Filtering Reports ZyWALL 2 Plus User s Guide 252 ...
Страница 265: ...Chapter 14 IPSec VPN ZyWALL 2 Plus User s Guide 265 Figure 178 SECURITY VPN VPN Rules IKE Edit Gateway Policy ...
Страница 274: ...Chapter 14 IPSec VPN ZyWALL 2 Plus User s Guide 274 Figure 181 SECURITY VPN VPN Rules IKE Edit Network Policy ...
Страница 306: ...Chapter 15 Certificates ZyWALL 2 Plus User s Guide 306 Figure 203 SECURITY CERTIFICATES My Certificates Create Basic ...
Страница 328: ...Chapter 16 Authentication Server ZyWALL 2 Plus User s Guide 328 ...
Страница 330: ...330 ...
Страница 346: ...Chapter 17 Network Address Translation NAT ZyWALL 2 Plus User s Guide 346 ...
Страница 350: ...Chapter 18 Static Route ZyWALL 2 Plus User s Guide 350 ...
Страница 398: ...Chapter 21 Remote Management ZyWALL 2 Plus User s Guide 398 ...
Страница 416: ...Chapter 24 ALG Screen ZyWALL 2 Plus User s Guide 416 ...
Страница 417: ...417 PART V Logs and Maintenance Logs Screens 419 Maintenance 447 ...
Страница 418: ...418 ...
Страница 423: ...Chapter 25 Logs Screens ZyWALL 2 Plus User s Guide 423 Figure 274 LOGS Log Settings ...
Страница 466: ...466 ...
Страница 474: ...Chapter 27 Introducing the SMT ZyWALL 2 Plus User s Guide 474 ...
Страница 496: ...Chapter 30 LAN Setup ZyWALL 2 Plus User s Guide 496 ...
Страница 504: ...Chapter 32 DMZ Setup ZyWALL 2 Plus User s Guide 504 ...
Страница 508: ...Chapter 33 Wireless Setup ZyWALL 2 Plus User s Guide 508 ...
Страница 556: ...Chapter 38 Filter Configuration ZyWALL 2 Plus User s Guide 556 ...
Страница 570: ...Chapter 40 System Information Diagnosis ZyWALL 2 Plus User s Guide 570 ...
Страница 586: ...Chapter 41 Firmware and Configuration File Maintenance ZyWALL 2 Plus User s Guide 586 ...
Страница 594: ...Chapter 42 System Maintenance Menus 8 to 10 ZyWALL 2 Plus User s Guide 594 ...
Страница 598: ...Chapter 43 Remote Management ZyWALL 2 Plus User s Guide 598 ...
Страница 603: ...603 PART VII Troubleshooting and Specifications Troubleshooting 605 Product Specifications 613 ...
Страница 604: ...604 ...
Страница 612: ...Chapter 45 Troubleshooting ZyWALL 2 Plus User s Guide 612 ...
Страница 620: ...620 ...
Страница 644: ...Appendix B Pop up Windows JavaScripts and Java Permissions ZyWALL 2 Plus User s Guide 644 ...
Страница 668: ...Appendix E Importing Certificates ZyWALL 2 Plus User s Guide 668 ...
Страница 672: ...Appendix F Legal Information ZyWALL 2 Plus User s Guide 672 ...
Страница 678: ...Appendix G Customer Support ZyWALL 2 Plus User s Guide 678 ...