ZyXEL N4100 Guia Do Utilizador
Chapter 5 WAN/LAN
N4100 User’s Guide
72
DHCP
DHCP (Dynamic Host Configuration Protocol) allows clients to obtain TCP/IP
configuration at start-up from a server.
configuration at start-up from a server.
DNS Server Addresses
DNS (Domain Name System) maps a domain name to its corresponding IP
address and vice versa. The DNS server is extremely important because without
it, you must know the IP address of a computer before you can access it.
address and vice versa. The DNS server is extremely important because without
it, you must know the IP address of a computer before you can access it.
There are two ways that an ISP disseminates the DNS server addresses.
• 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, enter them in the DNS Server fields.
• Some ISPs choose to disseminate the DNS server addresses using the DNS
server extensions of IPCP (IP Control Protocol) after the connection is up. If
your ISP did not give you explicit DNS servers, chances are the DNS servers are
conveyed through IPCP negotiation.
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.
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 N4100, which makes it accessible
from an outside network. It is used by the N4100 to communicate with other
devices in other networks. It can be static (fixed) or dynamically assigned by the
ISP each time the N4100 tries to access the Internet.
from an outside network. It is used by the N4100 to communicate with other
devices in other networks. It can be static (fixed) or dynamically assigned by the
ISP each time the N4100 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 PPTP server IP address if you
use the PPTP encapsulation method).
subnet mask and DNS server IP address(es) (and a PPTP server IP address if you
use the PPTP encapsulation method).
Maximum Transmission Unit
A maximum transmission unit (MTU) is the largest size packet or frame, specified
in octets (eight-bit bytes) that can be sent in a packet- or frame-based network.
The Transmission Control Protocol (TCP) uses the MTU to determine the maximum
size of each packet in any transmission. Too large an MTU size may mean
in octets (eight-bit bytes) that can be sent in a packet- or frame-based network.
The Transmission Control Protocol (TCP) uses the MTU to determine the maximum
size of each packet in any transmission. Too large an MTU size may mean