ZyXEL Communications NBG-417N, Руководство пользователя, Страница: 101 / 279

Chapter 8 WAN
User
’
s Guide
102
8.2.1 What You Need To Know
The following terms and concepts may help as you read through this chapter.
Encapsulation Method
Encapsulation is used to include data from an upper layer protocol into a lower
layer protocol. To set up a WAN connection to the Internet, you need to use the
same encapsulation method used by your ISP (Internet Service Provider). If your
ISP offers a dial-up Internet connection using PPPoE (PPP over Ethernet) or PPTP
(Point-to-Point Tunneling Protocol), they should also provide a username and
password (and service name) for user authentication.
WAN IP Address
The WAN IP address is an IP address for the NBG4115, which makes it accessible
from an outside network. It is used by the NBG4115 to communicate with other
devices in other networks. It can be static (fixed) or dynamically assigned by the
ISP each time the NBG4115 tries to access the Internet.
If your ISP assigns you a static WAN IP address, they should also assign you the
subnet mask and DNS server IP address(es) (and a gateway IP address if you use
the Ethernet or ENET ENCAP encapsulation method).
DNS Server Address Assignment
Use Domain Name System (DNS) to map a domain name to its corresponding IP
address and vice versa, for instance, the IP address of www.zyxel.com is
204.217.0.2. The DNS server is extremely important because without it, you must
know the IP address of a computer before you can access it.
The NBG4115 can get the DNS server addresses in the following ways.
1
The ISP tells you the DNS server addresses, usually in the form of an information
sheet, when you sign up. If your ISP gives you DNS server addresses, manually
enter them in the DNS server fields.
2
If your ISP dynamically assigns the DNS server IP addresses (along with the
NBG4115
’ s WAN IP address), set the DNS server fields to get the DNS server
address from the ISP.
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