19216811.liveWF200
802.11g Wireless Router
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Virtual Circuit (VC):
The Virtual Circuit (VC) properties of the ATM VC interface identify a unique
path that your ADSL/Ethernet router uses to communicate via the ATM-based network of ISP.
NAT Status:
This filed shows the current status of the NAT function for the current VC.
Number of IPs:
This field is to specify how many IPs are provided by your ISP for current VC. It can
be single IP or multiple IPs.
Note:
For VCs with single IP, they share the same DMZ & Virtual servers; for VCs with multiple IPs,
each VC cab set DMZ and Virtual servers. Furthermore, for VCs with multiple IPs, they can define the
Address Mapping rules; for VCs with single IP, since they have only one IP, there is no need to
individually define the Address Mapping rule.
6.3.1 What NAT Does
NAT changes the source IP address in a packet received from a subscriber (the inside local address) to
another (the inside global address) before forwarding the packet to the WAN side. When the response
comes back, NAT translates the destination address (the inside global address) back to the inside local
address before forwarding it to the original inside host. Note that the IP address (either local or global)
of an outside host is never changed.
The global IP addresses for the inside hosts can be either static or dynamically assigned by the ISP.
You may also designate servers, such as a Web server and a telnet server, on your local network and
make them accessible to the outside world. With no servers defined, your ROUTER filters out all
incoming inquiries, thus preventing intruders from probing your network. For more information on IP
address translation, refer to RFC 1631, The IP Network Address Translator (NAT).
Inside/outside indicates where a host is located relative to the ROUTER. The computers hosts of your
LAN are inside, while the Web servers on the Internet are outside.
Global/local indicates the IP address of a host in a packet as the packet traverses a router. The local
address refers to the IP address of a host when the packet is in the local network, while the global
address refers to the IP address of the host when the same packet is traveling in the WAN side.
Note that inside/outside refers to the location of a host, while global/local refers to the IP address of a
host used in a packet. Thus, an inside local address (ILA) is the IP address of an inside host of a packet
when the packet is still in the local network, while an inside global address (IGA) is the IP address of
the same inside host when the packet is on the WAN side.
The following table summarizes this information.
ITEM
DESCRIPTION
Inside
This refers to the host on the LAN.