Draytek Vigor130, User Manual

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Vigor130 Series User’s Guide 61
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.
Comment
–
Type a brief description for the entry.
Show Comment
–
Check this box to display the comment
on IP Bind List box.
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 or Update 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 .
Backup Store the configuration for Bind IP to MAC as a file.
Restore Restore the previously stored configuration file and apply to
such page.
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
modem might not be accessed.
When you finish the configuration, click OK to save the settings.
3
3
.
.
3
3
N
N
A
A
T
T
Usually, the modem serves as an NAT (Network Address Translation) modem. 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
modem, the modem will change its source address into the public IP address of the modem,
select the available public port, and then forward it. At the same time, the modem 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 modem’s public IP address
and the modem 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.