3Com OfficeConnect 3C840, Руководство пользователя

Страница: 28 / 222

1-8 C
HAPTER
1: O
VERVIEW
with an IP address for the workstation and the IP addresses of the default
router and Domain Name Server.
The OfficeConnect Remote 840 can be configured to be a DHCP Server,
with a pool of up to 40 IP addresses.
What is DNS?
A Domain Name Server (DNS) provides an IP address to a host computer
for a given domain name. A DNS Proxy receives requests and attempts to
find an entry in its local tables, and if one is not found, forwards the
request to a remote DNS Server. The remote DNS Server can be learned
dynamically through PPP or can be statically assigned.
The OfficeConnect Remote 840 can be configured as a DNS proxy. A
static local host entry of
ocrdsl-3com.com is configured for the
OfficeConnect Remote 840 by default. Therefore, the OfficeConnect
Remote 840 can be easily accessed with a web browser, by typing in
ocrdsl-3com.com in the location or address field in the browser.
In unconfigured mode, ocrdsl-3com.com is not configured by default. In
this mode, you will have to configure a static host entry.
What is Address
Translation?
Address Translation allows private network addresses to be mapped into
public addresses. The OfficeConnect Remote 840 provides two methods
for mapping private, non-registered LAN IP addresses to the public
Internet address(es) used for a wide-area connection. The two methods
are:
■
Network Address Translation (NAT). NAT simply substitutes public IP
addresses for private IP addresses.
■
Port Address Translation (PAT). PAT allows sessions from multiple
private IP addresses to use a single public IP address.
NAT and PAT can be configured for each remote site.
What is DHCP
Smart Mode?
To simplify the installation process, the OfficeConnect Remote 840 can be
initialized with a set of pre-configured parameters. This operational mode
is referred to as DHCP Smart Mode. In DHCP Smart Mode, the unit will
automatically be assigned an IP address and will provide a pool of IP
addresses to be assigned to each workstation attached to the LAN. When
840ug.book Page 8 Friday, July 7, 2000 2:23 PM