Vigor2133 Series User’s Guide
103
I
I
I
I
-
-
4
4
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.
Info
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.
Summary of Contents for Vigor2133 Vac
Page 1: ......
Page 12: ......
Page 119: ...Vigor2133 Series User s Guide 107...
Page 157: ...Vigor2133 Series User s Guide 145...
Page 176: ...Vigor2133 Series User s Guide 164 This page is left blank...
Page 210: ...Vigor2133 Series User s Guide 198 This page is left blank...
Page 285: ...Vigor2133 Series User s Guide 273...
Page 297: ...Vigor2133 Series User s Guide 285 The items categorized under OTHERS...
Page 321: ...Vigor2133 Series User s Guide 309...
Page 322: ...Vigor2133 Series User s Guide 310 This page is left blank...
Page 336: ...Vigor2133 Series User s Guide 324...
Page 356: ...Vigor2133 Series User s Guide 344...
Page 360: ...Vigor2133 Series User s Guide 348 Below shows the successful activation of Web Content Filter...
Page 401: ...Vigor2133 Series User s Guide 389...
Page 418: ...Vigor2133 Series User s Guide 406 This page is left blank...
Page 488: ...Vigor2133 Series User s Guide 476...
Page 494: ...Vigor2133 Series User s Guide 482...
Page 498: ...Vigor2133 Series User s Guide 486...
Page 500: ...Vigor2133 Series User s Guide 488 This page is left blank...
