Netgear DG834G user guide: Chapter 6: Advanced Configuration

Published by Netgear · pages 81–96 of 190 · Original PDF

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Chapter 6

Advanced Configuration

This chapter describes how to configure the advanced features of your 54 Mbps ADSL Modem Wireless Router Model DG834G.

Configuring Advanced Security

The 54 Mbps ADSL Modem Wireless Router Model DG834G provides a variety of advanced features, such as:

  • Setting up a Demilitarized Zone (DMZ) Server
  • Connecting Automatically, as Required
  • Disabling Port Scan and DOS Protection
  • Responding to a Ping on the Internet WAN Port
  • MTU Size
  • Flexibility on configuring your LAN TCP/IP settings
  • Using the Router as a DHCP Server
  • Configuring Dynamic DNS
  • Configuring Static Routes

These features are discussed below.

Advanced Configuration

Setting Up A Default DMZ Server

The Default DMZ Server feature is helpful when using some online games and videoconferencing applications that are incompatible with NAT. The modem router is programmed to recognize some of these applications and to work properly with them, but there are other applications that may not function well. In some cases, one local computer can run the application properly if that computer’s IP address is entered as the Default DMZ Server.

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Warning: For security reasons, you should avoid using the Default DMZ Server feature. When a computer is designated as the Default DMZ Server, it loses much of the protection of the firewall, and is exposed to many exploits from the Internet. If compromised, the computer can be used to attack your network.

Incoming traffic from the Internet is normally discarded by the modem router unless the traffic is a response to one of your local computers or a service that you have configured in the Ports menu. Instead of discarding this traffic, you can have it forwarded to one computer on your network. This computer is called the Default DMZ Server.

How to Configure a Default DMZ Server

To assign a computer or server to be a Default DMZ server, follow these steps:

  1. Log in to the modem router at its default LAN address of http://192.168.0.1 with its default User Name of admin, default password of password, or using whatever Password and LAN address you have chosen for the modem router.

Advanced Configuration

  1. From the Main Menu, under Advanced, click the WAN Setup link to view the page shown:

Figure from the manual

  1. Select the Default DMZ Server check box.
  2. Type the IP address for that server.
  3. Click Apply to save your changes.

Connect Automatically, as Required

Normally, this option should be enabled, so that an Internet connection will be made automatically, whenever Internet-bound traffic is detected. If this causes high connection costs, you can disable this setting.

If disabled, you must connect manually, using the sub-screen accessed from the "Connection Status" button on the Status screen.

If you have an "Always on" connection, this setting has no effect.

Disable Port Scan and DOS Protection

The Firewall protects your LAN against Port Scans and Denial of Service (DOS) attacks. This should be disabled only in special circumstances.

Advanced Configuration

Respond to Ping on Internet WAN Port

If you want the modem router to respond to a 'ping' from the Internet, select the Respond to Ping on Internet WAN Port check box. This should only be used as a diagnostic tool, since it allows your modem router to be discovered. Do not select this box unless you have a specific reason to do so.

MTU Size

The normal MTU (Maximum Transmit Unit) value for most Ethernet networks is 1500 Bytes, or 1492 Bytes for PPPoE connections. For some ISPs you may need to reduce the MTU. But this is rarely required, and should not be done unless you are sure it is necessary for your ISP connection.

Configuring LAN IP Settings

The LAN IP Setup menu allows configuration of LAN IP services such as DHCP and RIP. These features can be found under the Advanced heading in the Main Menu of the browser interface.

The modem router is shipped preconfigured to use private IP addresses on the LAN side, and to act as a DHCP server. The modem router’s default LAN IP configuration is:

• LAN IP addresses—192.168.0.1

• Subnet mask—255.255.255.0

Advanced Configuration

These addresses are part of the Internet Engineering Task Force (IETF)-designated private address range for use in private networks, and should be suitable in most applications. If your network has a requirement to use a different IP addressing scheme, you can make those changes in this menu.

Figure from the manual

The LAN TCP/IP Setup parameters are:

  • IP Address This is the LAN IP address of the modem router.

Warning: If you change the LAN IP address of the modem router while connected through the browser, you or anyone else using the router will be disconnected. You must then open a new connection to the new IP address and log in again. Others using the router will have to restart their computer and connect to the router again.

  • IP Subnet Mask This is the LAN Subnet Mask of the modem router. Combined with the IP address, the IP Subnet Mask allows a device to know which other addresses are local to it, and which must be reached through a gateway or modem router.

Advanced Configuration v1.0, January 2006 6-5

Figure from the manual

  • RIP Direction RIP (Router Information Protocol) allows a modem router to exchange routing information with other routers. The RIP Direction selection controls how the Modem Router sends and receives RIP packets. Both is the default. — When set to Both or Out Only, the modem router will broadcast its routing table periodically. — When set to Both or In Only, it will incorporate the RIP information that it receives. — When set to None, it will not send any RIP packets and will ignore any RIP packets received.

  • RIP Version This controls the format and the broadcasting method of the RIP packets that the modem router sends. It recognizes both formats when receiving. By default, this is set for RIP-1. — RIP-1 is universally supported. RIP-1 is probably adequate for most networks, unless you have an unusual network setup. — RIP-2 carries more information. Both RIP-2B and RIP-2M send the routing data in RIP-2 format. – RIP-2B uses subnet broadcasting. – RIP-2M uses multicasting.

DHCP

By default, the modem router will function as a DHCP (Dynamic Host Configuration Protocol) server, allowing it to assign IP, DNS server, and default gateway addresses to all computers connected to the modem router's LAN. The assigned default gateway address is the LAN address of the router. IP addresses will be assigned to the attached PCs from a pool of addresses specified in this menu. Each pool address is tested before it is assigned to avoid duplicate addresses on the LAN.

For most applications, the default DHCP and TCP/IP settings of the router are satisfactory. See “Internet Networking and TCP/IP Addressing” in Appendix C for an explanation of DHCP and information about how to assign IP addresses for your network.

Use Router as DHCP server

If another device on your network will be the DHCP server, or if you will manually configure the network settings of all of your computers, clear the ‘Use router as DHCP server’ check box. Otherwise, leave it selected.

Specify the pool of IP addresses to be assigned by setting the Starting IP Address and Ending IP Address. These addresses should be part of the same IP address subnet as the router’s LAN IP address. Using the default addressing scheme, you should define a range between 192.168.0.2 and 192.168.0.254, although you may want to save part of the range for devices with fixed addresses.

The router will deliver the following parameters to any LAN device that requests DHCP:

• An IP Address from the range you have defined

• Subnet Mask

• Gateway IP Address is the router’s LAN IP address

• Primary DNS Server, if you entered a Primary DNS address in the Basic Settings menu; otherwise, the router’s LAN IP address

• Secondary DNS Server, if you entered a Secondary DNS address in the Basic Settings menu

• WINS Server, short for Windows Internet Naming Service Server, determines the IP address associated with a particular Windows computer. A WINS server records and reports a list of names and IP address of Windows PCs on its local network. If you connect to a remote network that contains a WINS server, enter the server’s IP address here. This allows your PCs to browse the network using the Network Neighborhood feature of Windows.

Reserved IP addresses

When you specify a reserved IP address for a computer on the LAN, that computer will always receive the same IP address each time it access the router’s DHCP server. Reserved IP addresses should be assigned to servers that require permanent IP settings.

To reserve an IP address:

  1. Click the Add button.

  2. In the IP Address box, type the IP address to assign to the computer or server. Choose an IP address from the router’s LAN subnet, such as 192.168.0.x.

  3. Type the MAC Address of the computer or server.

Tip: If the computer is already present on your network, you can copy its MAC address from the Attached Devices menu and paste it here.

Advanced Configuration

  1. Click Apply to enter the reserved address into the table.

Note: The reserved address will not be assigned until the next time the computer contacts the router's DHCP server. Reboot the computer or access its IP configuration and force a DHCP release and renew.

To edit or delete a reserved address entry:

  1. Click the button next to the reserved address you want to edit or delete.
  2. Click Edit or Delete.

How to Configure LAN TCP/IP Settings

  1. Log in to the router at its default LAN address of http://192.168.0.1 with its default User Name of admin, default password of password, or using whatever User Name, Password and LAN address you have chosen for the router.
  2. From the Main Menu, under Advanced, click the LAN IP Setup link to view the menu, shown:

Figure from the manual

  1. Enter the TCP/IP, DHCP, or Reserved IP parameters.
  2. Click Apply to save your changes.

Configuring Dynamic DNS

If your network has a permanently assigned IP address, you can register a domain name and have that name linked with your IP address by public Domain Name Servers (DNS). However, if your Internet account uses a dynamically assigned IP address, you will not know in advance what your IP address will be, and the address can change frequently. In this case, you can use a commercial dynamic DNS service that will allow you to register your domain to their IP address, and will forward traffic directed at your domain to your frequently-changing IP address.

The router contains a client that can connect to a dynamic DNS service provider. To use this feature, you must select a service provider and obtain an account with them. After you have configured your account information in the router, whenever your ISP-assigned IP address changes, your router will automatically contact your dynamic DNS service provider, log in to your account, and register your new IP address.

How to Configure Dynamic DNS

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Warning: If your ISP assigns a private WAN IP address such as 192.168.x.x or 10.x.x.x, the dynamic DNS service will not work because private addresses will not be routed on the Internet.

  1. Log in to the router at its default LAN address of http://192.168.0.1 with its default User Name of admin, default password of password, or using whatever User Name, Password and LAN address you have chosen for the router.

Advanced Configuration

  1. From the Main Menu of the browser interface, under Advanced, select Dynamic DNS to display the page below.

Figure from the manual

  1. Access the Web site of one of the dynamic DNS service providers whose names appear in the 'Service Provider' box, and register for an account. For example, for dyndns.org, go to www.dyndns.org.
  2. Select the Use a dynamic DNS service check box.
  3. Select the name of your dynamic DNS Service Provider.
  4. Type the Host Name that your dynamic DNS service provider gave you. The dynamic DNS service provider may call this the domain name. If your URL is myName.dyndns.org, then your Host Name is "myName."
  5. Type the User Name for your dynamic DNS account.
  6. Type the Password (or key) for your dynamic DNS account.
  7. If your dynamic DNS provider allows the use of wildcards in resolving your URL, you can select the Use wildcards check box to activate this feature. For example, the wildcard feature will cause *.yourhost.dyndns.org to be aliased to the same IP address as yourhost.dyndns.org
  8. Click Apply to save your configuration.

Advanced Configuration

Using Static Routes

Static Routes provide additional routing information to your router. Under normal circumstances, the router has adequate routing information after it has been configured for Internet access, and you do not need to configure additional static routes. You must configure static routes only for unusual cases such as multiple routers or multiple IP subnets located on your network.

Static Route Example

As an example of when a static route is needed, consider the following case:

  • Your primary Internet access is through a cable modem to an ISP.
  • You have an ISDN router on your home network for connecting to the company where you are employed. This router’s address on your LAN is 192.168.0.100.
  • Your company’s network is 134.177.0.0.

When you first configured your router, two implicit static routes were created. A default route was created with your ISP as the modem router, and a second static route was created to your local network for all 192.168.0.x addresses. With this configuration, if you attempt to access a device on the 134.177.0.0 network, your router will forward your request to the ISP. The ISP forwards your request to the company where you are employed, and the request will likely be denied by the company’s firewall.

In this case you must define a static route, telling your router that 134.177.0.0 should be accessed through the ISDN router at 192.168.0.100. The static route would look like Figure 6-6.

In this example:

  • The Destination IP Address and IP Subnet Mask fields specify that this static route applies to all 134.177.x.x addresses.
  • The Modem Router IP Address fields specifies that all traffic for these addresses should be forwarded to the ISDN router at 192.168.0.100.
  • A Metric value of 1 will work since the ISDN router is on the LAN. This represents the number of routers between your network and the destination. This is a direct connection so it is set to 1.
  • Private is selected only as a precautionary security measure in case RIP is activated.

Advanced Configuration v1.0, January 2006 6-11

How to Configure Static Routes

  1. Log in to the router at its default LAN address of http://192.168.0.1 with its default User Name of admin, default password of password, or using whatever User Name, Password and LAN address you have chosen for the router.
  2. From the Main Menu of the browser interface, under Advanced, click Static Routes to view the Static Routes menu, shown in Figure 6-5.

Figure from the manual

Figure 6-5

  1. To add or edit a Static Route: a. Click the Edit button to open the Edit Menu, shown in Figure 6-6.

Figure from the manual

Figure 6-6

b. Type a route name for this static route in the Route Name box under the table. This is for identification purpose only. c. Select Private if you want to limit access to the LAN only. The static route will not be reported in RIP.

Advanced Configuration

d. Select Active to make this route effective. e. Type the Destination IP Address of the final destination. f. Type the IP Subnet Mask for this destination. If the destination is a single host, type 255.255.255.255. g. Type the Gateway IP Address, which must be a router on the same LAN segment as the router. h. Type a number between 1 and 15 as the Metric value. This represents the number of routers between your network and the destination. Usually, a setting of 2 or 3 works, but if this is a direct connection, set it to 1. 4. Click Apply to have the static route entered into the table.

Universal Plug and Play (UPnP)

Universal Plug and Play (UPnP) helps devices, such as Internet appliances and computers, access the network and connect to other devices as needed. UPnP devices can automatically discover the services from other registered UPnP devices on the network.

  1. Click UPnP on the main menu to invoke the UPnP menu:

Figure from the manual

Figure 6-7 2. Fill out the UPnP screen:

  • Turn UPnP On: UPnP can be enabled or disabled for automatic device configuration. The default setting for UPnP is enabled. If disabled, the Router will not allow any device to automatically control the resources, such as port forwarding (mapping), of the Router.

Advanced Configuration

  • Advertisement Period: The Advertisement Period is how often the Router will advertise (broadcast) its UPnP information. This value can range from 1 to 1440 minutes. The default period is for 30 minutes. Shorter durations will ensure that control points have current device status at the expense of additional network traffic. Longer durations may compromise the freshness of the device status but can significantly reduce network traffic.
  • Advertisement Time To Live: The time to live for the advertisement is measured in hops (steps) for each UPnP packet sent. A hop is the number of steps allowed to propagate for each UPnP advertisement before it disappears. The number of hops can range from 1 to 255. The default value for the advertisement time to live is 4 hops, which should be fine for most home networks. If you notice that some devices are not being updated or reached correctly, then it may be necessary to increase this value a little.
  • UPnP Portmap Table: The UPnP Portmap Table displays the IP address of each UPnP device that is currently accessing the Router and which ports (Internal and External) that device has opened. The UPnP Portmap Table also displays what type of port is opened and if that port is still active for each IP address.
  1. To save, cancel or refresh the table: a. Click Apply to save the new settings to the Router. b. Click Cancel to disregard any unsaved changes. c. Click Refresh to update the portmap table and to show the active ports that are currently opened by UPnP devices.

6-14 Advanced Configuration

Chapter 7

Virtual Private Networking

This chapter describes how to use the virtual private networking (VPN) features of the ADSL Modem Wireless Router. VPN communications paths are called tunnels. VPN tunnels provide secure, encrypted communications between your local network and a remote network or computer. See “Virtual Private Networking (VPN)” in Appendix C to learn more about VPN.

This chapter is organized as follows:

  • “Overview of VPN Configuration” on page 7-2 provides an overview of the two most common VPN configurations: Client-to-Gateway and Gateway-to-Gateway.
  • “Planning a VPN” on page 7-4 provides a worksheet for recording the configuration parameters of the VPN you want to set up, along with the VPN Committee (VPNC) recommended default parameters set by the VPN Wizard.
  • “VPN Tunnel Configuration” on page 7-6 summarizes the three ways to configure a VPN tunnel: VPN Wizard (recommended for most situations), Auto Policy, and Manual Policy.
  • “How to Set Up a Client-to-Gateway VPN Configuration” on page 7-7 provides the steps needed to configure a VPN tunnel between a remote PC and a network gateway using the VPN Wizard and the NETGEAR ProSafe VPN Client.
  • “How to Set Up a Gateway-to-Gateway VPN Configuration” on page 7-21 provides the steps needed to configure a VPN tunnel between two network gateways using the VPN Wizard.
  • “VPN Tunnel Control” on page 7-29 provides the step-by-step procedures for activating, verifying, deactivating, and deleting a VPN tunnel once the VPN tunnel has been configured.
  • “How to Set Up VPN Tunnels in Special Circumstances” on page 7-38 provides the steps needed to configure VPN tunnels when there are special circumstances and the VPNC recommended defaults of the VPN Wizard are inappropriate. The two alternatives for configuring VPN tunnels are Auto Policy and Manual Policy.

Virtual Private Networking

Overview of VPN Configuration

Two common scenarios for configuring VPN tunnels are between a remote personal computer and a network gateway and between two or more network gateways. The DG834G v3 supports both of these types of VPN configurations. The ADSL Modem Wireless Router supports up to five concurrent tunnels.

Client-to-Gateway VPN Tunnels

Client-to-Gateway VPN Tunnels provide secure access from a remote PC, such as a telecommuter connecting to an office network.

Figure from the manual

Figure 7-1

A VPN client access allows a remote PC to connect to your network from any location on the Internet. In this case, the remote PC is one tunnel endpoint, running the VPN client software. The ADSL Modem Wireless Router on your network is the other tunnel endpoint. See “How to Set Up a Client-to-Gateway VPN Configuration” on page 7-7 to set up this configuration.

Virtual Private Networking

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