ZyWALL Series Internet Security Gateway
IP Subnetting
M-7
Chart M-12 Class C Subnet Planning
NO. “BORROWED” HOST BITS
SUBNET MASK
NO. SUBNETS NO. HOSTS PER SUBNET
1 255.255.255.128
(/25)
2
126
2 255.255.255.192
(/26)
4
62
3 255.255.255.224
(/27)
8
30
4 255.255.255.240
(/28)
16
14
5 255.255.255.248
(/29)
32
6
6 255.255.255.252
(/30)
64
2
7 255.255.255.254
(/31)
128
1
Subnetting With Class A and Class B Networks.
For class “A” and class “B” addresses the subnet mask also determines which bits are part of the network
number and which are part of the host ID.
A class “B” address has two host ID octets available for subnetting and a class “A” address has three host ID
octets (see
Chart M-1
) available for subnetting.
The following table is a summary for class “B” subnet planning.
Chart M-13 Class B Subnet Planning
NO. “BORROWED” HOST BITS
SUBNET MASK
NO. SUBNETS
NO. HOSTS PER SUBNET
1 255.255.128.0
(/17)
2 32766
2 255.255.192.0
(/18)
4 16382
3 255.255.224.0
(/19)
8
8190
4 255.255.240.0
(/20)
16 4094
5 255.255.248.0
(/21)
32 2046
6 255.255.252.0
(/22)
64 1022
7 255.255.254.0
(/23)
128 510
8 255.255.255.0
(/24)
256 254
Summary of Contents for Internet Security Gateway ZyWALL 100
Page 1: ...ZyWALL 10W 30W 50 100 Internet Security Gateway User s Guide Version 3 62 February 2004 ...
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Page 124: ...ZyWALL Series Internet Security Gateway 8 16 WAN Screens Figure 8 10 Dial Backup Setup ...
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Page 235: ...ZyWALL Series Internet Security Gateway VPN Screens 15 11 Figure 15 5 VPN IKE ...
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Page 282: ...ZyWALL Series Internet Security Gateway 16 20 Certificates Figure 16 9 Trusted CA Details ...
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Page 351: ...Logs IX Part IX Logs This part provides information and instructions for the logs and reports ...
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Page 356: ...ZyWALL Series Internet Security Gateway 20 4 Log Screens Figure 20 2 Log Settings ...
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Page 365: ...Maintenance X Part X Maintenance This part covers the maintenance screens ...
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