Netgear C3700 N600 Wifi Cable Modem Router User Manual

							Specify Internet Port Settings 91
 N600 WiFi Cable Modem Router Model C3700
5. 
Select the Port Triggering  radio button.
6. Select a radio button to specify when you want to use port triggering:
• Never . 
The modem router does not use port triggering even if you have specified\
 port 
triggering settings.
• Per Schedule. Port triggering is used based on the settings in the Schedule screen.
• Always . 
 Always use port triggering.
7.  In the Port T
 riggering Timeout  field, enter a value up to 9999 minutes. 
This value controls how long the inbound ports stay open when the modem \
router detects  no activity
 . This value is required because the modem router cannot detect when the 
application terminates.
Application Example: Port Triggering for Internet Relay Chat 
Some application servers, such as FTP and IRC servers, send replies to m\
ultiple port 
numbers. Using port triggering, you can tell the modem router to open mo\
re incoming ports 
when a particular outgoing port starts 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 modem router, “When you initiate a session with destination \
port 6667, you must also 
allow incoming traffic on port 113 to reach the originating computer.” The following sequence 
shows the effects of the port triggering rule you have defined:
1.  Y
ou open an IRC client program to start a chat session on your computer. 
2. Y
our IRC client composes a request message to an IRC server using a desti\
nation port 
number of 6667, the standard port number for an IRC server process. Your computer then 
sends this request message to your  modem router.
3.  Y
our  modem router  creates an entry in its internal session table describing this 
communication session between your computer and the IRC server. Your  modem 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.  
						

							Specify Internet Port Settings 
92 N600 WiFi Cable Modem Router Model C3700 
4. Noting your port triggering rule and observing the destination port number of 6667, your 
modem router creates another session entry to send any incoming port 113 traffic to your 
computer.
5. The IRC server sends a return message to your modem router using the NAT-assigned 
source port (for example, port 33333) as the destination port. The IRC server also sends an 
“identify” message to your modem router with destination port 113.
6. When your modem router receives the incoming message to destination port 33333, it 
checks its session table to see if a session is active for port number 33333. Finding an active 
session, the modem router restores the original address information replaced by NAT and 
sends this reply message to your computer.
7. When your modem router receives the incoming message to destination port 113, it checks 
its session table and finds an active session for port 113 associated with your computer. The 
modem 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 modem router eventually senses a period of 
inactivity in the communications. The modem router then removes the session information 
from its session table, and incoming traffic is no longer accepted on port numbers 33333 or 
113. 
						

							93
9
9.   Troubleshooting
This chapter gives information about troubleshooting your modem router. 
This chapter includes the following sections:
•Use LEDs to Troubleshoot 
•Cannot Log In to the Modem Router 
•Cannot Log In to the Modem Router 
•Troubleshoot a TCP/IP Network Using a Ping Utility 
Tip:NETGEAR provides helpful articles, documentation, and the latest 
software updates at 
support.netgear.com. 
						

							Troubleshooting 94
N600 WiFi Cable Modem Router Model C3700 
Use LEDs to Troubleshoot
The following table provides help when using the LEDs for troubleshootin\
g.
Table 3.  LED troubleshooting
LED BehaviorAction
All LEDS are off when the modem  router is plugged in. Make sure that the power cord is properly connected to your modem 
router and that the power adapter is properly connected to a 
functioning power outlet. 
Check that you are using the 12 VDC power adapter from NETGEAR 
for this product.
If the error persists, you have a hardware problem. Contact technical 
support.
All LEDs stay on. • Clear the configuration of the modem router to its factory defaults. 
This operation sets the IP address of the modem router to  192.168.0.1. See  Factory Default Settings on page  99. 
•  If the error persists, you have a hardware problem. Contact 
technical support.
LAN LED is off for a port with an 
Ethernet connection. • 
Make sure that the Ethernet cable connections are secure at the 
modem router and at the hub or computer

.
•  Make sure that power is turned on to the connected hub or 
computer

.
•  Be sure that you are using the correct cable.
Internet LED is off and the modem 
router is connected to the cable 
television cable. • 
Make sure that the coaxial cable connections are secure at the 
modem router and at the wall jack.
•  Make sure that your cable service provider has provisioned your 
cable Internet service. 

Your provider can verify that the signal 
quality is good enough for modem router service.
•  Remove any excessive splitters that you have on your cable line. 
Run a “home run” back to the point where the cable enters your 
home.
Cannot Log In to the Modem Router
If you cannot access the modem router from a computer on your local netw\
ork, check the 
following:
• If you are using a WiFi connection, check to make sure that your compute\
r or mobile 
device is connected to the correct WiFi network.
• If your computer is connected to the modem router wtih an Ethernet cable\
, check the 
connection.
• Make sure that your computer
 ’s IP address is on the same subnet as the modem router. 
If you are using the recommended addressing scheme, the address of your \
computer is 
in the range of 192.168.0.10 to 192.168.0.254.  
						

							Troubleshooting 
95  N600 WiFi Cable Modem Router Model C3700
Note:If the IP address of your computer is shown as 169.254.x.x: 
Recent versions of Windows and Mac OS generate and assign an IP 
address when the computer cannot reach a DHCP server. These 
autogenerated addresses are in the range of 169.254.x.x. If your IP 
address is in this range, check the connection from the computer to 
the modem router and reboot your computer.
•If the IP address of your modem router has been changed and you do not know its 
current IP address, clear the configuration of the modem router to its factory defaults. 
This sets the IP address of the modem router to 192.168.0.1. For more information, see 
Factory Default Settings on page 99.
•Make sure that your browser has Java, JavaScript, or ActiveX enabled. If you are using 
Internet Explorer, click the Refresh button to make sure that the Java applet is loaded.
•Try quitting the browser and launching it again.
•Make sure that you are using the correct login information. The modem router user name 
admin is lowercase (Caps Lock is off). The default password is password. 
If the modem router does not save changes you have made, do the following:
•When entering configuration settings, be sure to click the Apply button before moving to 
another screen, or your changes are lost. 
•Click the Refresh or Reload button in the web browser. The changes have occurred, but 
the web browser might be caching the old configuration.
Troubleshoot the ISP Connection
When your modem router cannot access the Internet and your Internet LED is on, register 
the cable MAC address or device MAC address of your modem router with your cable service 
provider. 
Additionally, your computer might not have the modem router configured as its TCP/IP 
gateway. If your computer obtains its information from the modem router by DHCP, reboot the 
computer and verify the gateway address.
Troubleshoot a TCP/IP Network Using a Ping Utility
Most TCP/IP terminal devices and routers contain a ping utility that sends an echo request 
packet to the designated device. The device then responds with an echo reply. You can 
easily troubleshoot a TCP/IP network by using the ping utility in your computer or 
workstation. 
						

							Troubleshooting 
96 N600 WiFi Cable Modem Router Model C3700 
Use PIng to Test the LAN Path to Your Gateway
You can use ping to verify that the LAN path to your modem router is set up correctly.
To ping the modem router from a computer running Windows 95 or later:
1. From the Windows toolbar, click the Start button and select Run.
2. In the field that is provided, type ping and then the IP address of the modem router, as in 
this example:
ping 192.168.0.1
3. Click OK.
You see a message like the following:
Pinging  with 32 bytes of data
If the path is working, you see this message:
Reply from < IP address >: bytes=32 time=NN ms TTL=xxx
If the path is not working, you see this message:
Request timed out
If the path is not working correctly, you could have one of the following problems:
•Wrong physical connections.
-Make sure that the LAN LED is lit. If this LED is off. for more information, see Use 
LEDs to Troubleshoot on page 94.
-Check the corresponding link LEDs are on for your network interface card and the 
hub ports (if any) that are connected to your workstation and modem router.
•Wrong network configuration.
-Verify that the Ethernet card driver software and TCP/IP software are both 
installed and configured on your computer or workstation.
-Verify that the IP address for your modem router and your workstation are correct 
and that the addresses are on the same subnet.
Use Ping to Test the Path from a Windows PC to a Remote 
Device
After verifying that the LAN path works correctly, test the path from the Windows PC to a 
remote device. 
To test the path from a Windows PC to a remote device:
1. From the Windows run menu, type: ping -n 10 
where  is the IP address of a remote device such as the DNS server of your 
ISP. 
						

							Troubleshooting 
97  N600 WiFi Cable Modem Router Model C3700
If the path is working, you see this message:
Reply from < IP address >: bytes=32 time=NN ms TTL=xxx
2. If you do not receive this reply, do the following:
•Check that the Internet LED is lit.
•If your ISP assigned a host name to your computer, enter that host name as the 
account name in the Internet Setup screen.
•Check that your computer has the IP address of your modem router is listed as the 
default gateway. If DHCP assigns the IP configuration of your computer, this 
information is not visible in the Network Control Panel of your computer. Verify that 
the IP address of the modem router is listed as the default gateway. 
•Check that the network address of your computer (the portion of the IP address 
specified by the netmask) is different from the network address of the remote device. 
						

							98
A
A.   Supplemental Information
This appendix includes the following sections.
•Factory Default Settings 
•Technical Specifications  
						

							 Supplemental Information99
 N600 WiFi Cable Modem Router Model C3700
Factory Default Settings
You can return the modem router to its factory default settings. 
To restore the factory default settings:
1. 
Locate the small hole in the bottom of the modem router
 .
The reset button is located inside this hole.
2.  Use a paperclip or sharp object to press and hold the  Reset button for over seven seconds. 
Designed by NETGEAR in California
The modem router resets and returns to the factory settings shown in the\
 following table.
Factory Default Settings   
Gateway loginUser login URL http://192.168.0.1
User name and password 
(case-sensitive) admin / password
Local network 
(LAN) LAN IP
192.168.0.1
Subnet mask 255.255.255.0
DHCP server Enabled
DHCP starting IP address 192.168.0.2
DHCP ending IP address 192.168.0.254
Firewall Inbound communication from the 
Internet Disabled (except traffic on port 80, the HTTP port)
Outbound communication to the 
Internet Enabled (all)
Source MAC filtering Disabled
Internet 
connection WAN MAC address
Use default hardware address 
						

							 Supplemental Information
100 N600 WiFi Cable Modem Router Model C3700 
Technical Specifications
The following table describes the technical specifications for the modem router.
WirelessWireless communicationEnabled
SSID nameAs shown on the product label
SecurityWPA/WPA2.  
The default WPA/WPA2 passphrase is on the 
product label.
Broadcast SSIDEnabled
Transmission speedAuto1
Country/regionUnited States in the US; otherwise varies by region
RF channelAuto
Operating modea, n, g, and b
Data rateBest
Output powerFull
Access pointEnabled
Authentication typeOpen System
Wireless card access listAll wireless stations allowed
1. Maximum wireless signal rate derived from IEEE Standard 802.11 specifications. Actual throughput will 
vary. Network conditions and environmental factors, including volume of network traffic, building materials 
and construction, and network overhead, may lower actual data throughput rate.
Table 4.  Technical specifications
Technical Specifications 
Network protocol and 
standards compatibilityData and routing protocols: TCP/IP, DHCP server and client, DNS relay, NAT 
(many-to-one), and TFTP client
Power adapter• North America:  120V,  60  Hz,  input
• All regions (output): 12V DC @ 1.5A output 18W maximum
Physical specifications• Dimensions: 7.60 x 4.45 x 1.63 in. (193.04 x 113.03 x 41.40 mm)
• Weight: 0.775 lb (0.352 kg)
Environmental• Operating temperature: –22° to 122°F (–30° to 50°C)
• Operating humidity: 90% maximum relative humidity, noncondensing
• Electromagnetic emissions: Meets requirements of: FCC Part 15 Class B.
Factory Default Settings  (continued)