Zyxel NBG-418N v2 - Инструкция по эксплуатации - Страница 167

 Appendix B IP Addresses and Subnetting

NBG-418N v2 User’s Guide

167

You can obtain your IP address from the IANA, from an ISP, or it can be assigned from a private network. 
If you belong to a small organization and your Internet access is through an ISP, the ISP can provide you 
with the Internet addresses for your local networks. On the other hand, if you are part of a much larger 
organization, you should consult your network administrator for the appropriate IP addresses.

Regardless of your particular situation, do not create an arbitrary IP address; always follow the guidelines 
above. For more information on address assignment, please refer to RFC 1597, Address Allocation for 
Private Internets and RFC 1466, Guidelines for Management of IP Address Space.

IP A d d re ss C o nflic ts

Each device on a network must have a unique IP address. Devices with duplicate IP addresses on the 
same network will not be able to access the Internet or other resources. The devices may also be 
unreachable through the network. 

C o nflic ting  C o m p ute r IP A d d re sse s Exa m p le

More than one device can not use the same IP address. In the following example computer 

A  

has a 

static (or fixed) IP address that is the same as the IP address that a DHCP server assigns to computer 

B

which is a DHCP client. Neither can access the Internet. This problem can be solved by assigning a 
different static IP address to computer 

A

 or setting computer 

A

 to obtain an IP address automatically. 

Fig ure  1 2 1    

Conflicting Computer IP Addresses Example

C o nflic ting  Ro ute r IP A d d re sse s Exa m p le

Since a router connects different networks, it must have interfaces using different network numbers. For 
example, if a router is set between a LAN and the Internet (WAN), the router’s LAN and WAN addresses 
must be on different subnets. In the following example, the LAN and WAN are on the same subnet. The 
LAN computers cannot access the Internet because the router cannot route between networks.