Netgear Wireless N 150 Router Wnr612 User Guide

							  Chapter 5:  Maintenance      | 
    51
Wireless-N 150 Router WNR612v2 User Manual 
Enabling Remote Management Access
Using the Remote Management feature, you can allow a user on the Interne\
t to configure, 
upgrade, and check the status of your wireless router. Select Remote Man\
agement under 
Advanced in the main menu.
 The Remote Management screen displays.
Note:  
Be sure to change the router’s default configuration password to a 
very secure password. The ideal password should contain no 
dictionary words from any language, and should be a mixture of 
letters (both uppercase and lowercase), numbers, and symbols. 
Your password can be up to 30 characters.
To configure your router for remote management:
1.  Select the Turn Remote Management On  check box.
2.  Under Allow Remote Access By, specify what external IP addresses will be\
 allowed to 
access the router’s remote management.
Note:   For enhanced security, restrict access to as few external IP 
addresses as practical. 
						

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Traffic Meter
Traffic Metering allows you to monitor the volume of Internet traffic pa\
ssing through your 
router’s Internet port. With the Traffic Meter utility, you can set l\
imits for traffic volume, set a 
monthly limit, and get a live update of traffic usage.
To monitor traffic on your router:
1. 
Under the Advanced heading, select 
Traffic Meter.
2. To enable the Traffic Meter, click the 
Enable Traffic Meter  check box.
3.  If you would like to record and restrict the 
volume of Internet traffic, click the  Traffic 
volume control  by radio button. You can 
select one of the following options for 
controlling the traffic volume:
•     No Limit – No restriction is applied  when the traffic limit is reached.
•     Download only – The restriction is  applied to incoming traffic only.
•     Both Directions – The restriction is  applied to both incoming and outgoing 
traffic.
4.  You can limit the amount of data traffic 
allowed per month:
•     By specifying how many Mbytes per  month are allowed. 
•     By specifying how many hours of traffic are allowed.
5.  Set the  Traffic Counter to begin at a specific time and date.
6.  Set up  Traffic Control to issue a warning message before the month limit of Mbytes or 
Hours is reached. You can select one of the following to occur when the \
limit is attained:
•     The Internet LED flashes green or amber. 
•     The Internet connection is disconnected and disabled.
7.  Set up  Internet Traffic Statistics to monitor the data traffic.
8.  Click the  Traffic Status  button if you want a live update on Internet traffic status on your 
router.
9.  Click  Apply to save your settings. 
						

							  Chapter 6:  Fine-Tuning Your Network     |     53
6.   Fine-Tuning Your Network
6
This chapter describes how to modify the configuration of the wireless r\
outer to allow specific 
applications to access the Internet or to be accessed from the Internet,\
 and how to make 
adjustments to enhance your network’s performance.
This chapter includes the following sections: •     Allowing Inbound Connections to Your Network  on page
  54
•     Configuring Port Forwarding to Local Servers  on page
  58
•     Configuring Port Triggering  on page
  60
•     Using Universal Plug and Play  on page
  62
•     Changing the MTU Size on page  63
•     Quality of Service on page  65
•     Overview of Home and Small Office Networking Technologies  on page
  69 
						

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Allowing Inbound Connections to Your Network
By default, the wireless router blocks any inbound traffic from the Internet to your computers 
except for replies to your outbound traffic. However, you might need to create exceptions to 
this rule for the following 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 their replies are not 
recognized by your router.
Your router provides two features for creating these exceptions: port forwarding and port 
triggering. This section explains how a normal outbound connection works, followed by two 
examples explaining how port forwarding and port triggering operate and how they differ.
How Your Computer Accesses the Internet through Your Router
To access a computer on the Internet, your computer sends the router a message containing 
source and destination address and process information. Your router modifies the source 
information and creates and tracks 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 an Internet browser such as Internet Explorer. Invisible to you, your operating 
system assigns a service number (port number) to every communication process 
running on your computer. In this example, let’s say Windows assigns port number 5678 
to this browser session. 
2. You select a Web page such as www.example.com. Your computer composes a Web page 
request message with the following address and port information: 
•     The source address is your computer’s IP address.
•     The source port number is 5678, the browser session. 
•     The destination address is the IP address of www.example.com, which your computer 
finds by asking a DNS server.
•     The destination port number is 80, the standard port number for a Web server 
process.
Your computer sends this request message to your router.
3. Your router creates an entry in its session table describing this communication session 
between your computer and the Web server at 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 router replaces the source address (your computer’s private IP address) with it’s 
public IP address. 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. 
						

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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 source address is the IP address of www.example.com.
•     The source port number is 80, the standard port number for a Web server process.
•     The destination address is the public IP address of your router.
•     The destination port number is 33333.
The Web server then sends this reply message to your router.
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, restoring the original address information replaced by 
NAT. The message now contains the following address and port information: 
•     The source address is the IP address of www.example.com.
•     The source port number is 80, the standard port number for a Web server process.
•     The destination address is your computer’s IP address.
•     The destination port number is 5678, the browser session that made the initial 
request.
Your router sends this reply message to your computer, which displays the Web page 
from www.example.com.
6. When you finish your browser session, your router eventually senses 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.
How Port Triggering Changes the Communication Process
Usually, during an Internet session your computer sends outbound requests. The router 
sends replies to same port number where the session is. Replies to a different port number, 
are discarded. However, some application servers (such as FTP and IRC servers) send 
replies to multiple port numbers. With port triggering, you can tell the router to open more 
incoming ports when a particular outgoing port originates a session.
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 must 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, beginning 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. 
						

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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, let’s 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. You can usually determine this information by contacting the publisher of the 
application, or user groups or news groups.
Note:  Only one computer at a time can use the triggered application.
How Port Forwarding Changes the Communication Process
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 
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 our 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: 
						

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1. The user of a remote computer opens Internet Explorer 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: 
•     The destination address is the IP address of www.example.com, which is the address 
of your router.
•     The destination port number is 80, 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 Network Address Translation (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. 
You usually can determine this information by contacting the publisher of the application or 
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.
•     Port triggering does not need to know the computer’s IP address in advance. The IP 
address is captured automatically.
•     Port forwarding requires that you specify the computer’s IP address during configuration, 
and the IP address must never change.
•     Port triggering requires specific outbound traffic to open the inbound ports, and the 
triggered ports are closed after a period of no activity.
•     Port forwarding is always active and does not need to be triggered. 
						

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Configuring Port Forwarding to Local Servers
With port forwarding, you can allow certain types of incoming traffic to\
 reach servers on your 
local network. For example, you might make a local Web server, FTP serve\
r, or game server 
visible and available to the Internet. 
Use the Port Forwarding screen to configure the router to forward specif\
ic 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. The 
DMZ server is configured in the WAN Setup screen, as discussed in Setting Up a Default 
DMZ Server on page
 39.
Before starting, you need to determine which type of service, applicatio\
n, or game you will 
provide, and the local IP address of the computer that will provide the \
service. Be sure the 
computer’s IP address never changes.
Tip:  To ensure that your server computer always has the same IP address, 
use the reserved IP address feature of your wireless router. See Using 
Address Reservation  on page
  36.
To configure port forwarding to a local server:
1.  Select Port Forwarding/Port Triggering under Advanced in the main menu. \
The Port 
Forwarding/Port Triggering screen displays
.
2.  From the Service Name list, select the service or game that you will host on your network.  
If it is not in the list, see the following section,  Adding a Custom Service.”
3.  In the corresponding  Server IP Address fields, enter the last digit of the IP address of your 
local computer that will provide this service. 
4.  To the right of Server IP Address, click  Add. The service appears in the list in the screen.
Adding a Custom Service
To define a service, game, or application that does not appear in the  Service Name list, you 
must first find out which port number or range of numbers is used by the\
 application. You can 
contact the publisher of the application or user groups or news groups. \
 
						

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To add a custom service:
1. 
Select Port Forwarding/Port Triggering under Advanced in the main menu.
2.  Click  Add Service. The Ports–Custom Services screen displays.
 
3.  In the Service Name field, enter a descriptive name. 
4.  In the Service Type  field, select the protocol. If you are unsure, select  TCP/UDP.
5.  In the Starting Port  field, enter the beginning port number. 
•     If the application uses only a single port, enter the same port number i\
n the Ending  Port field.
•     If the application uses a range of ports, enter the ending port number o\
f the range in  the Ending Port field.
6.  In the  Server IP Address field, enter the IP address of your local computer that will provide 
this service.
7.  Click  Apply . The service appears in the list in the Port Forwarding/Port Triggering\
 screen.
Editing or Deleting a Port Forwarding Entry
To edit or delete a port forwarding entry:
1. In the table, select the button next to the service name.
2. Click  Edit Service or  Delete Service to make changes.
3.  Click  Apply .
Application Example: Making a Local Web Server Public
If you host a Web server on your local network, you can use port forward\
ing to allow Web 
requests from anyone on the Internet to reach your Web server.  
						

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To make a local Web server public:
1. Assign your Web server either a fixed IP address or a dynamic IP address using DHCP 
address reservation, as explained in 
Using Address Reservation on page 36. In this 
example, your router will always give your Web server an IP address of 192.168.1.33. 
2. In the Port Forwarding screen, configure the router to forward the HTTP service to the local 
address of your Web server at 192.168.1.33. 
 
HTTP (port 80) is the standard protocol for Web servers.
3. (Optional) Register a host name with a Dynamic DNS service, and configure your router to 
use the name as described in 
Using the Router as a DHCP Server on page 35.  
To access your Web server from the Internet, a remote user must know the IP address that 
has been assigned by your ISP. However, if you use a Dynamic DNS service, the remote 
user can reach your server by a user-friendly Internet name, such as mynetgear.dyndns.org.
Configuring Port Triggering
Port triggering is a dynamic extension of port forwarding that is useful in these cases:
•     More than one local computer needs port forwarding for the same application (but not 
simultaneously).
•     An application needs to open incoming ports that are different from the outgoing port.
When port triggering is enabled, the router monitors outbound traffic looking for a specified 
outbound “trigger” port. When the router detects outbound traffic on that port, it remembers 
the IP address of the local computer that sent the data. The router then temporarily opens the 
specified incoming port or ports, and forwards incoming traffic on the triggered ports to the 
triggering computer. 
While port forwarding creates a static mapping of a port number or range to a single local 
computer, port triggering can dynamically open ports to any computer that needs them and 
can close the ports when they are no longer needed.
Note:  If you use applications such as multiplayer gaming, peer-to-peer 
connections, real-time communications such as instant messaging, 
or remote assistance (a feature in Windows XP), you should also 
enable Universal Plug and Play (UPnP). See 
Using Universal Plug 
and Play on page 62.
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. You can usually determine this information by contacting the publisher of the 
application or user groups or news groups.