Edge-Core VG007, Руководство по управлению

Страница: 31 / 86

NAT
3-7
3
NAT
Network Address Translation (NAT) is a standard method of mapping multiple
"internal" IP addresses to one "external" IP address on devices at the edge of a
network. For the Pocket VoIP Gateway, the internal (local) IP addresses are the IP
addresses assigned to PCs and wireless clients by the DHCP server, and the
external IP address is the IP address assigned to the WAN port.
Virtual Server
Using the NAT Virtual Server feature, remote users can access different servers on
your local network using your single public IP address.
Remote users accessing services such as web or FTP at your local site thorugh
your public IP address, are redirected (mapped) to other local server IP addresses
and TCP/UDP port numbers. For example, if you set Type/Public Port to TCP/80
(HTTP or web) and the Private IP/Port to 192.168.7.9/80, then all HTTP requests
from outside users forwarded to 192.168.7.9 on port 80. Therefore, by just using
your external IP address provided by your ISP, Internet users can access the
services they need at the local addresses to which you redirect them.
The more common TCP service port numbers include: HTTP: 80, FTP: 21, Telnet:
23, and POP3: 110.
Figure 3-6. Gateway Mode Virtual Server
• Private IP – The IP address of the server on the local Ethernet network. The
specified address must be in the same subnet as the Pocket VoIP Gateway and its
DHCP server address pool.
• Private Port – Specifies the port number used on the local server for the service.
• Type – Specifies the port type. (Options: TCP or UDP; Default: TCP)