UTT Technologies Chapter 7 Advanced
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For example, if you want to allow the local SMTP server (IP address: 192.168.1.88) to be
available to the outside users, you can create a port forwarding entry: external IP address
is WAN1 IP address (200.200.201.88 in this example), external port is 2100, internal IP
address is 192.168.1.88, and internal port is 25. Then all the requests to SMTP service
from outside users to 200.200.201.88:2100 will be forwarded to 192.168.1.88:25.
2. DMZ Host
The DMZ (Demilitarized Zone) feature allows one local computer to be exposed to the
Internet for the use of a special service such as online game or video conferencing. When
receiving the requests initiated from outside users, the Router will directly forward these
requests to the specified DMZ host.
Note
When a local computer is designated as the DMZ host, it loses firewall protection
provided by the Router. As the DMZ host is exposed to many exploits from the
Internet, it may be used to attack your network.
3. The Priorities of Port Forwarding Entries and DMZ Host
The port forwarding entries take priority over the DMZ host. When receiving a request
packet initiated from an outside user, the Router will firstly search the
Port Forwarding
List
to find out if there is a port forwarding entry matching the destination IP address and
port of the packet. If a match is found, the Router will forward the packet to the mapped
local computer. Else, the Router will try to find out if there is an available DMZ host.
7.1.2 Port Forwarding
7.1.2.1 Port Forwarding List
Figure 7-1 Port Forwarding List
