Appendix A IP Addresses and Subnetting

The following table is a summary for subnet planning on a network with a 16-bit network number.

Table 79 16-bit Network Number Subnet Planning

NO. “BORROWED”

SUBNET MASK

NO.

NO. HOSTS PER

HOST BITS

SUBNETS

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

 

 

 

 

9

255.255.255.128 (/25)

512

126

 

 

 

 

10

255.255.255.192 (/26)

1024

62

 

 

 

 

11

255.255.255.224 (/27)

2048

30

 

 

 

 

12

255.255.255.240 (/28)

4096

14

 

 

 

 

13

255.255.255.248 (/29)

8192

6

 

 

 

 

14

255.255.255.252 (/30)

16384

2

 

 

 

 

15

255.255.255.254 (/31)

32768

1

 

 

 

 

Configuring IP Addresses

Where you obtain your network number depends on your particular situation. If the ISP or your network administrator assigns you a block of registered IP addresses, follow their instructions in selecting the IP addresses and the subnet mask.

If the ISP did not explicitly give you an IP network number, then most likely you have a single user account and the ISP will assign you a dynamic IP address when the connection is established. If this is the case, it is recommended that you select a network number from 192.168.0.0 to 192.168.255.0. The Internet Assigned Number Authority (IANA) reserved this block of addresses specifically for private use; please do not use any other number unless you are told otherwise. You must also enable Network Address Translation (NAT) on the NBG-417N.

Once you have decided on the network number, pick an IP address for your NBG- 417N that is easy to remember (for instance, 192.168.1.1) but make sure that no other device on your network is using that IP address.

The subnet mask specifies the network number portion of an IP address. Your NBG-417N will compute the subnet mask automatically based on the IP address

NBG-417N User’s Guide

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ZyXEL Communications NBG-417N manual Configuring IP Addresses, 213, bit Network Number Subnet Planning