Wireless Cable Voice Gateway Model CBVG834G Adminstrators User Manual

Protecting Your Network

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Forwarding Inbound Traffic

To forward inbound traffic:

1.

Select the service that you want to forward from the

Predefined Services

drop-down list.

If the service that you want to forward is not in the predefined list, you can add a custom

service. Enter the range of ports that you want to forward and select whether the ports are TCP,

UDP or Both.

2.

If you want to change the suggested port numbers, enter a new

Start Port

and

End Port

.

3.

From the drop-down

Protocol

list, select the protocol: TCP, UDP, or Both.

4.

Enter the IP address of the computer on your network to which you would like to direct the

inbound traffic in the

Local IP Address

field.

5.

Click

Add

. The new Port Forwarding rule is added to the Active Forwarding Rules table.

Deleting a Rule

To delete an existing rule:

1.

Select the radio button for the rule that you want to delete.

2.

Click

Delete

to delete the Port Forwarding rule.

Figure 3-7

Wireless Cable Voice Gateway Model CBVG834G Adminstrators User Manual

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Port Triggering

Port Triggering is an advanced feature that allows you to dynamically open inbound ports based on

outbound traffic on different ports. This feature can be used for gaming and other Internet

applications.

Port Triggering monitors outbound traffic. When the gateway detects traffic on the specified

outbound port, it remembers the IP address of the computer that sent the data and “triggers” the

incoming port. Incoming traffic on the triggered port is then forwarded to the triggering computer.

For example, port triggering can be used for Internet Relay Chat (IRC). When you connect to an

IRC server, the server tries to connect back on the port to do an Ident lookup. Unless you have

configured Port Forwarding to open that port, the traffic will be blocked. In this example, the

initial login to the server in the range of ports is detected. This triggers the gateway to temporarily

forward the port to the PC that initiated the login.

Note:

Port Forwarding is similar to port triggering, but it is static and has some

limitations. Ports are open to traffic from the Internet until the port forwarding rule

is removed. Additionally, port forwarding does not work well for some

applications when your WAN IP address is assigned by DHCP, and is changed

frequently. Port Triggering opens an incoming port temporarily and does not

require the server on the internet to track your IP address if it is changed.

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To configure Port Triggering:

1.

On the main menu, select Port Triggering. The Port Triggering screen displays:

2.

In the

Trigger Range

field, enter the outbound ports that will be monitored for activity. This

will be the “trigger.”

3.

In the

Target Range

field, enter the inbound ports that should be forwarded when the trigger

occurs.

4.

Select the appropriate protocol: TCP, UDP or Both.

5.

Select the

Enable

check box

6.

Click

Apply

.

There are two ways to clear a Port Triggering rule:

•

Clear the

Enable

check box to temporarily disable the rule.

•

Select the rule, and then click

Delete

.

Figure 3-8

Wireless Cable Voice Gateway Model CBVG834G Adminstrators User Manual

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Setting Up a DMZ Host

The Default DMZ Server feature is helpful when using some online games and video conferencing

applications that are incompatible with NAT. The gateway 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 PC can run the application properly if that PC’s IP address

is entered as the Default DMZ Host.

Incoming traffic from the Internet is normally discarded by the gateway unless the traffic is a

response to one of your local computers or a service that you have configured in the Port

Forwarding or Port Triggering screen. Instead of discarding this traffic, you can have it forwarded

to one computer on your network. This computer is called the default DMZ host.

To assign a computer or server to be a DMZ host:

1.

From the main menu, under the Advanced heading, select DMZ Host. The DMZ Host screen

displays:

2.

In the

DMZ Address

field, enter the IP address of the computer that you want to assign as a

DMZ host.

3.

Click

Apply

.

To disable the DMZ host, enter

0

(zero), and then click

Apply

.

If you want the gateway to respond to a ping from the Internet, select the

Respond to Ping on

WAN Port

check box. This should only be used as a diagnostic tool, since it allows your gateway

to be discovered. Do not select this check box unless you have a specific reason to do so.

Note:

For security, 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.

Figure 3-9

Managing Your Network

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Chapter 4

Managing Your Network

This chapter describes how to perform network management tasks such as viewing the gateway

status, running diagnostics, restoring factory default settings, and backing up your configuration

files. For information about the Guest Network and WMM features, see

“Guest Network” on

page 2-14

and

“Wi-Fi Multimedia (WMM)” on page 2-14

.

Gateway Status

Under the Maintenance heading on the main menu, select Gateway Status to display the following

screen:

The Gateway Status fields are described in the following table:

Figure 4-1

Table 4-1. Gateway Status Screen Settings

Setting

Description

Standard Specification

Compliant

DOCSIS 2.0. This is the specification to which the gateway’s cable

interface is compatible.

Hardware Version

The hardware version of the gateway.