Netgear Centria Wndr4700 Wndr4720 Media Storage Router User Manual

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 CENTRIA WNDR4700/WNDR4720
Wireless AP
The CENTRIA can be configured as a wireless 
AP. This mode lets you add a second router to 
your network. To use the wireless AP feature, you need two routers: one set up as a router 
and the other set up as a wireless AP. 
For example, you could install the first router  in a ro
 om like a home office that has your 
Internet connection. Then, set up the second router as a wireless AP. Place the router that is 
an AP in a different room that has your home entertainment center. Cable the router that is a 
wireless AP to your Smart TV, DVR, game co nsole or Blu-ray player, and then use its 
802.11ac WiFi connection to the first router. 
To set up a router as a wireless access point:
1.  Make sure t
 hat your router has an Internet connection and that wireless devices can 
connect to it.
2.  Select  Advanc
 ed > Advanced Setup > Wireless AP .
3. Select the  Enable Access Point Mode  radio button.
4.  Click  App
 ly. 
						

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Wireless Repeating Function (WDS)
You can set the CENTRIA up to be used as a wire
less access point (AP). Doing this enables 
the router to act as a wireless repeater. A wireless repeater connects to another wireless 
router as a client where the network to which it connects becomes the ISP service.
Wireless repeating is a type of Wireless Distri butio
 n System (WDS). A WDS allows a wireless 
network to be expanded through multiple access points instead of using a wired backbone to 
link them. The following figure shows a wireless repeating scenario.
Repeater
Base station access point
access point
Figure 9. Wireless repeating scenario
Note:  If you use the wireless repeating function, you need to select either  WEP or None as a security option in the Wireless Settings screen. 
The WEP option displays only if you select the wireless mode Up to 
54 Mbps in the Wireless Settings screen.
Wireless base station . The router acts as the parent access point, bridging traffic to and 
from the child repeater access point. The base st ation also handles wireless and wired local 
computers. To configure this mode, you have to know the MAC addresses of the child 
repeater access point.
Wireless repeater . Th
 e router sends all traffic from its local wireless or wired computers to a 
remote access point. To configure this m ode, you have to know the MAC address of the 
remote parent access point.  
						

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The router is always in dual-band concurrent mode, unless you turn off one radio. If you 
enable the wireless repeater in either radio band, the wireless base station or wireless 
repeater cannot be enabled in the other radio band. However, if you enable the wireless base 
station in either radio band and use the other radio band as a wireless router or wireless base 
station, dual-band concurrent mode is not affected.
For you to set up a wireless network with WDS, both access points must meet the following 
condition

s:
•      Both acce
 ss points have to use the same SSID, wireless channel, and encryption mode.
•      Both acce
 ss points have to be on the same LAN IP subnet. That is, all the access point 
LAN IP addresses are in the same network.
•      All L
AN devices (wired and wireless computers) are configured to operate in the same 
LAN network address range as the access points.
To view or change the Wireless Repeating Function settings: 
Select  Adva
 nced > Advanced Setup > Wireless Repeating  to view or change wireless 
repeater settings for the router.
Scroll to view 
more settings
The following settings are available:
•      Enable 
 Wireless Repeating Function . Select the check box for the 2.4  GHz or 5 GHz 
n
etwork to use the wireless repeating function.
•      W
ireless MAC of this router . This field displays the MAC address for your router for 
your reference. You need to enter this MAC address in the corresponding Wireless 
Repeating Function screen of the other access point you are using.
•      W
ireless Repeater . If your router is the repeater, select this check box. 
						

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104 CENTRIA WNDR4700/WNDR4720 
Repeater IP Address. If your router is the repeater, enter the IP address of the other 
access point.
Disable Wireless Client Association. If your router is the repeater, selecting this check 
box means that wireless clients cannot associate with it. Only LAN client associations are 
allowed.
-If you are setting up a point-to-point bridge, select this check box. 
-If you want all client traffic to go through the other access point (repeater with wireless 
client association), leave this check box cleared.
Base Station MAC Address. If your router is the repeater, enter the MAC address for the 
access point that is the base station.
•     Wireless Base Station. If your router is the base station, select this check box.
Disable Wireless Client Association. If your router is the base station, selecting this 
check box means that wireless clients cannot associate with it. Only LAN client 
associations are allowed.
Repeater MAC Address (1 through 4). If your router is the base station, it can act as the 
“parent” of up to four other access points. Enter the MAC addresses of the other access 
points in these fields.
Set Up the Base Station 
The wireless repeating function works only in hub and spoke mode. The units cannot be 
daisy-chained. You have to know the wireless settings for both units. You have to know the 
MAC address of the remote unit. First, set up the base station, and then set up the repeater.
To set up the base station:
1. Set up both units with the same wireless settings (SSID, mode, channel, and security). 
The wireless security option must be set to None or WEP. 
						

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2. 
Select  Advanced > Advanced Setup > Wireless Repeating Function  to display the 
Wireless Repeating Function screen.
Scroll to view 
more settings
3.  Select the Enable Wireless Repeating Function  check box and select the Wireless Base 
Station  radio button.
4.  Ente
r the MAC address for one or more repeater units.
5. Click  App
 ly to save your changes.
Set Up a Repeater Unit
Use a wired Ethernet connection to set up the repeater unit to avoid conflicts with the 
wireless connection to the base station.
Note:   If you are using the WNDR4700/WNDR4720 base station with a 
non-NETGEAR router as the repeater, you might need to change 
additional configuration settings. In  particular, you should disable the 
DHCP server function on the wireless repeater AP.
To configure the router as a repeater unit:
1.  L
og in to the router that will be the repeater. 
2. Select  Basic > W
 ireless Settings and verify that the wireless settings match the base unit 
exactly. The wireless security option must be set to None or WEP.
3.  Select  Ad
 vanced > Wireless Repeating Function , and select the Enable Wireless 
Repeating Function  check box and the Wireless Repeater radio button. 
						

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4. Fill in the Repeater IP Address field. This IP address must be in the same subnet as the 
base station, but different from the LAN IP address of the base station.
5. Click Apply to save your changes.
6. Verify connectivity across the LANs. 
A computer on any wireless or wired LAN segment of the router can connect to the 
Internet or share files and printers with any other wireless or wired computer or server 
connected to the other access point.
Port Forwarding and Triggering
By default, the router blocks inbound traffic from the Internet to your computers except replies 
to your outbound traffic. You might need to create exceptions to this rule for these purposes:
•     To allow remote computers on the Internet to access a server on your local network. 
•     To allow certain applications and games to work correctly when your router does not 
recognize their replies.
Your router provides two features for creating these exceptions: port forwarding and port 
triggering. The next sections provide background information to help you understand how 
port forwarding and port triggering work, and the differences between the two.
Remote Computer Access Basics
When a computer on your network needs to access a computer on the Internet, your 
computer sends your router a message containing the source and destination address and 
process information. Before forwarding your message to the remote computer, your router 
has to modify the source information and create and track the communication session so that 
replies can be routed back to your computer. 
Here is an example of normal outbound traffic and the resulting inbound responses:
1. You open a browser and your operating system assigns port number 5678 to this 
browser session. 
2. You type http://www.example.com into the URL field, and your computer creates a web page 
request message with the following address and port information. The request message is 
sent to your router.
Source address. Your computer’s IP address.
Source port number. 5678, which is the browser session. 
Destination address. The IP address of www.example.com, which your computer finds 
by asking a DNS server.
Destination port number. 80, which is the standard port number for a web server 
process.
3. Your router creates an entry in its internal session table describing this communication 
session between your computer and the web server at www.example.com. Before sending  
						

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the web page request message to www.example.com, your router stores the original 
information and then modifies the source information in the request message, performing 
Network Address Translation (NAT):
•     The source address is replaced with your router’s public IP address. This is necessary 
because your computer uses a private IP address that is not globally unique and cannot 
be used on the Internet.
•     The source port number is changed to a number chosen by the router, such as 33333. 
This is necessary because two computers could independently be using the same 
session number.
Your router then sends this request message through the Internet to the web server at 
www.example.com.
4. The web server at www.example.com composes a return message with the requested web 
page data. The return message contains the following address and port information. The 
web server then sends this reply message to your router.
Source address. The IP address of www.example.com.
Source port number. 80, which is the standard port number for a web server process.
Destination address. The public IP address of your router.
Destination port number. 33333.
5. Upon receiving the incoming message, your router checks its session table to determine 
whether there is an active session for port number 33333. Finding an active session, the 
router then modifies the message to restore the original address information replaced by 
NAT. Your router sends this reply message to your computer, which displays the web page 
from www.example.com. The message now contains the following address and port 
information.
Source address. The IP address of www.example.com.
Source port number. 80, which is the standard port number for a web server process.
Destination address. Your computer’s IP address.
Destination port number. 5678, which is the browser session that made the initial 
request.
6. When you finish your browser session, your router eventually detects a period of inactivity in 
the communications. Your router then removes the session information from its session 
table, and incoming traffic is no longer accepted on port number 33333.
Port Triggering to Open Incoming Ports
In the preceding example, requests are sent to a remote computer by your router from a 
particular service port number. Replies from the remote computer to your router are directed 
to that port number. If the remote server sends a reply to a different port number, your router 
does not recognize it and discards it. However, some application servers (such as FTP and 
IRC servers) send replies to multiple port numbers. Using the port triggering function of your 
router, you can tell the router to open additional incoming ports when a particular outgoing 
port originates a session. 
						

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An example is Internet Relay Chat (IRC). Your computer connects to an IRC server at 
destination port 6667. The IRC server not only responds to your originating source port, but 
also sends an “identify” message to your computer on port 113. Using port triggering, you can 
tell the router, “When you initiate a session with destination port 6667, you have to also allow 
incoming traffic on port 113 to reach the originating computer.” Using steps similar to the 
preceding example, the following sequence shows the effects of the port triggering rule you 
have defined:
1. You open an IRC client program to start a chat session on your computer. 
2. Your IRC client composes a request message to an IRC server using a destination port 
number of 6667, the standard port number for an IRC server process. Your computer 
then sends this request message to your router.
3. Your router creates an entry in its internal session table describing this communication 
session between your computer and the IRC server. Your router stores the original 
information, performs Network Address Translation (NAT) on the source address and 
port, and sends this request message through the Internet to the IRC server. 
4. Noting your port triggering rule and having observed the destination port number of 
6667, your router creates an additional session entry to send any incoming port 113 
traffic to your computer.
5. The IRC server sends a return message to your router using the NAT-assigned source 
port (as in the previous example, say port 33333) as the destination port. The IRC 
server also sends an “identify” message to your router with destination port 113.
6. Upon receiving the incoming message to destination port 33333, your router checks its 
session table to determine whether there is an active session for port number 33333. 
Finding an active session, the router restores the original address information replaced 
by NAT and sends this reply message to your computer.
7. Upon receiving the incoming message to destination port 113, your router checks its 
session table and learns that there is an active session for port 113, associated with 
your computer. The router replaces the message’s destination IP address with your 
computer’s IP address and forwards the message to your computer.
8. When you finish your chat session, your router eventually senses a period of inactivity in 
the communications. The router then removes the session information from its session 
table, and incoming traffic is no longer accepted on port numbers 33333 or 113.
To configure port triggering, you need to know which inbound ports the application needs. 
Also, you need to know the number of the outbound port that will trigger the opening of the 
inbound ports. Usually, you can determine this information by contacting the publisher of the 
application or the relevant user groups or news groups.
Note:  Only one computer at a time can use the triggered application.
Port Forwarding to Permit External Host Communications
In both of the preceding examples, your computer initiates an application session with a 
server computer on the Internet. However, you might need to allow a client computer on the  
						

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109  CENTRIA WNDR4700/WNDR4720
Internet to initiate a connection to a server computer on your network. Normally, your router 
ignores any inbound traffic that is not a response to your own outbound traffic. You can 
configure exceptions to this default rule by using the port forwarding feature. 
A typical application of port forwarding can be shown by reversing the client-server 
relationship from the previous web server example. In this case, a remote computer’s 
browser needs to access a web server running on a computer in your local network. Using 
port forwarding, you can tell the router, “When you receive incoming traffic on port 80 (the 
standard port number for a web server process), forward it to the local computer at 
192.168.1.123.” The following sequence shows the effects of the port forwarding rule you 
have defined:
1. The user of a remote computer opens a browser and requests a web page from 
www.example.com, which resolves to the public IP address of your router. The remote 
computer composes a web page request message with the following destination 
information: 
Destination address. The IP address of www.example.com, which is the address of your 
router.
Destination port number. 80, which is the standard port number for a web server 
process.
The remote computer then sends this request message through the Internet to your 
router.
2. Your router receives the request message and looks in its rules table for any rules 
covering the disposition of incoming port 80 traffic. Your port forwarding rule specifies 
that incoming port 80 traffic should be forwarded to local IP address 192.168.1.123. 
Therefore, your router modifies the destination information in the request message:
The destination address is replaced with 192.168.1.123.
Your router then sends this request message to your local network.
3. Your web server at 192.168.1.123 receives the request and composes a return message 
with the requested web page data. Your web server then sends this reply message to 
your router.
4. Your router performs NAT on the source IP address, and sends this request message 
through the Internet to the remote computer, which displays the web page from 
www.example.com.
To configure port forwarding, you need to know which inbound ports the application needs. 
Usually, you can determine this information by contacting the publisher of the application or 
the relevant user groups or news groups.
How Port Forwarding Differs from Port Triggering
The following points summarize the differences between port forwarding and port triggering:
•     Port triggering can be used by any computer on your network, although only one 
computer can use it at a time.
•     Port forwarding is configured for a single computer on your network. 
						

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•     
Port triggering does not require that you know the computer’s IP address in advance. The 
IP address is captured automatically.
•      Po
rt forwarding requires that you specify the  computer’s IP address during configuration, 
and the IP address can never change.
•      Port t
riggering requires specific outbound traffic to open the inbound ports, and the 
triggered ports are closed after a period of no activity.
•      Port f
orwarding is always active and does not need to be triggered.
Set Up Port Forwarding to Local Servers
Using the port forwarding feature, you can allow certain types of incoming traffic to reach 
servers on your local network. For example, you might want to make a local web server, FTP 
server, or game server visible and available to the Internet.
Use the Port Forwarding screen to configure the  route
 r to forward specific incoming protocols 
to computers on your local network. In addition to servers for specific applications, you can 
also specify a default DMZ server to which all other incoming protocols are forwarded.
Before starting, determine which type of servic e, a
 pplication, or game you want to provide. 
Find out the local IP address of the computer  that will provide the service. The server 
computer has to always have the same IP address.
To set up port forwarding:
Tip:  T
o ensure that your server computer always has the same IP address, 
use the reserved IP address feature of your CENTRIA. 
1.  Select  Advance
 d Setup > Port Forwarding/Port Triggering  to display the following 
screen:
Port Forwarding is selected as the service type.
2.  From the Service Name list, sele ct the service or game 
 that you will host on your network. If 
the service does not appear in the list, see  Add a Custom Service on p
 age 111 .
3.  In
 the corresponding Server IP Address field, enter the last digit of the IP address of your 
local computer that will provide this service. 
4.  Click  Add. The
  service appears in the list in the screen.