ZyXEL Communications 645R-A Series User Manual

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Prestige 645R-A Series User’s Guide 
4-6 
Wizard Setup 
4.7.4 Private IP Addresses 
Every machine on the Internet must have a unique address. If your networks are isolated from the Internet, 
for example, only between your two branch offices, you can assign any IP addresses to the hosts without 
problems. However, the Internet Assigned Numbers Authority (IANA) has reserved the following three 
blocks of IP addresses specifically for private networks: 
10.0.0.0     —  10.255.255.255 
172.16.0.0   —  172.31.255.255 
192.168.0.0  —  192.168.255.255 
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. 
4.8  Nailed-Up Connection (PPP) 
A nailed-up connection is a dial-up line where the connection is always up regardless of traffic demand. The 
Prestige does two things when you specify a nailed-up connection. The first is that idle timeout is disabled. 
The second is that the Prestige will try to bring up the connection when turned on and whenever the 
connection is down. A nailed-up connection can be very expensive for obvious reasons.  
Do not specify a nailed-up connection unless your telephone company offers flat-rate service or you need a 
constant connection and the cost is of no concern 
4.9 NAT 
NAT (Network Address Translation - NAT, RFC 1631) is the translation of the IP address of a host in a 
packet, for example, the source address of an outgoing packet, used within one network to a different IP 
address known within another network. 
4.10  Wizard Setup Configuration: Second Screen 
The second wizard screen varies depending on what protocol you use. All screens shown are with routing 
mode. Configure the fields and click Next to continue.