Draytek VigorFly 210, Руководство пользователя

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VigorFly 210 Series User’s Guide 63
Add or Update IP Address
–
Type the IP address that will be used for the
specified MAC address.
Mac Address
–
Type the MAC address that is used to bind
with the assigned IP address.
IP Bind List It displays a list for the IP bind to MAC information.
Add - It allows you to add the one you choose from the ARP
table or the IP/MAC address typed in Add and Edit to the
table of IP Bind List .
Update - It allows you to edit and modify the selected IP
address and MAC address that you create before.
Delete - You can remove any item listed in IP Bind List .
Simply click and select the one, and click Delete . The
selected item will be removed from the IP Bind List .
After finishing all the settings here, please click OK to save the configuration.
Note: Before you select Strict Bind , you have to bind one set of IP/MAC address for one
PC. If not, no one of the PCs can access into Internet. And the web user interface of the
router might not be accessed.
3 3 . . 3 3 N N A A T T
Usually, the router serves as an NAT (Network Address Translation) router. NAT is a
mechanism that one or more private IP addresses can be mapped into a single public one.
Public IP address is usually assigned by your ISP, for which you may get charged. Private IP
addresses are recognized only among internal hosts.
When the outgoing packets destined to some public server on the Internet reach the NAT
router, the router will change its source address into the public IP address of the router, select
the available public port, and then forward it. At the same time, the router shall list an entry in
a table to memorize this address/port-mapping relationship. When the public server response,
the incoming traffic, of course, is destined to the router’s public IP address and the router will
do the inversion based on its table. Therefore, the internal host can communicate with external
host smoothly.
The benefit of the NAT includes:

Save cost on applying public IP address and apply efficient usage of IP address.
NAT allows the internal IP addresses of local hosts to be translated into one public IP
address, thus you can have only one IP address on behalf of the entire internal hosts.

Enhance security of the internal network by obscuring the IP address. There are
many attacks aiming victims based on the IP address. Since the attacker cannot be aware
of any private IP addresses, the NAT function can protect the internal network.
On NAT page, you will see the private IP address defined in RFC-1918. Usually we use the
192.168.1.0/24 subnet for the router. As stated before, the NAT facility can map one or
more IP addresses and/or service ports into different specified services. In other words, the
NAT function can be achieved by using port mapping methods.
Below shows the menu items for NAT.