ZyXEL Communications P-662HW-63, Руководство пользователя

Страница: 64 / 561

Prestige 662HW Series User’s Guide
Chapter 3 Wizard Setup for Internet Access 64
3.2.1.4 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.
3.2.2 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
3.2.3 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.
3.2.4 Internet Access Wizard Setup: Second Screen
The second wizard screen varies depending on what mode and encapsulation type you use. All
screens shown are with routing mode. Configure the fields and click
Next to continue.
Note: 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.