Gateway Configuration Screen Definitions

SURFboard® SBG6580 Wireless Cable Modem Gateway

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User Guide

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MAC Filtering

MAC filtering allows you to define up to twenty Media Access Control (MAC) address filters to prevent

computers from sending outgoing TCP/UDP traffic to the WAN via their MAC addresses. This is useful

because the MAC address of a specific NIC card never changes, unlike its IP address, which can be

assigned via the DHCP server or hard-coded to various addresses over time.

Figure 44 – Advanced MAC Filtering Screen

Table 13: Advanced MAC Filtering-Field Descriptions

Field

Description

Add MAC

Address

Enter the MAC address for the computer you want to

block and click

Add MAC Address

button.

Repeat for up to 20 MAC addresses.

Remove MAC Address

Enter the MAC address filter that you want to delete

block and click

Remove MAC Address

button.

Clear All button

Deletes all of your MAC Address filters.

Port Filtering

Port filtering allows you to define port filters to prevent all devices from sending outgoing TCP/UDP

traffic to the WAN on specific IP port numbers. By specifying a starting and ending port range, you can

determine what TCP/UDP traffic is allowed out to the WAN on a per-port basis.

Note

: The specified port ranges are blocked for ALL computers, and this setting is not IP address or MAC

address specific. For example, if you wanted to block all computers on your home network from accessing

HTTP sites (or web surfing), you would create the following port filter and then click

Apply

when done:

•

Set

Start Port

to

80

•

Set

End Port

to

80

•

Set

Protocol

to

TCP

•

Select

Enabled

Gateway Configuration Screen Definitions

SURFboard® SBG6580 Wireless Cable Modem Gateway

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User Guide

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365-095-25397-x.1

Figure 45 – Advanced Port Filtering Screen

Table 14: Advanced Port Filtering-Field Descriptions

Field

Description

Start Port

The starting port number of the Port Filtering range.

End Port

The ending port number of the Port Filtering range.

Protocol

Select

TCP

,

UDP

, or

BOTH

from the drop-down list.

Enabled

Select to activate or deselect to deactivate the selected IP

port triggers.

Port Triggers

You can use Port Triggers to configure dynamic triggers to specific devices on the LAN. This allows

special applications that require specific port numbers with bi-directional traffic to function properly.

Applications such as video conferencing, voice, gaming, and some messaging program features may

require these special settings.

Figure 46 – Advanced Create Port Triggers Screen

Gateway Configuration Screen Definitions

SURFboard® SBG6580 Wireless Cable Modem Gateway

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User Guide

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Figure 47 – Advanced Port Triggers Screen

Table 15: Advanced Port Triggers-Field Descriptions

Field

Description

Trigger Start Port

The starting port number of the Port Trigger range.

Trigger End Port

The ending port number of the Port Trigger range.

Target Start Port

The starting port number of the Port Target range.

Target End Port

The ending port number of the Port Target range.

Protocol

Available protocols:

TCP

,

UDP

, or

BOTH

Description

Name to identify the port trigger.

Enabled

Lets you turn

On

or

Off

the selected IP port triggers.

Port Forwarding

Port forwarding allows you to run a publicly accessible server on your home network by specifying the

mapping of TCP/UDP ports to a local computer. This enables incoming requests on specific port

numbers to reach web servers, FTP servers, and mail servers, for example; so that they can be accessible

from the Internet.

To map a port, you must enter the range of port numbers that want forwarded locally and the IP

address to which traffic to those ports should be sent. If you only want a single port specification, enter

the same port number in the start and end locations for that IP address.

Gateway Configuration Screen Definitions

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User Guide

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A table of commonly used port numbers is also displayed on the page for your convenience. These are

some of the ports used by common applications:

Figure 48 – Commonly Used Port Forwarding Port Numbers List

Figure 49 – Advanced Create Port Forwarding Screen

Figure 50 – Advanced Port Forwarding Screen

Gateway Configuration Screen Definitions

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User Guide

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Table 16: Advanced Port Forwarding-Field Descriptions

Field

Description

External IP Address &

Start/End Port

The range of ports that you want to allow for incoming

traffic to be forwarded from a remote IP address.

Local IP Address &

Start/End Port

The range of ports that you want to allow for incoming

traffic to be forwarded from a local IP address.

Description

Name to identify the port trigger.

Protocol

Available protocols:

TCP

,

UDP

, or

BOTH

Enabled

Lets you turn

On

or

Off

port forwarding.

DMZ Host

You can configure one computer on your home network as the DMZ Host. That computer will operate

outside of the SBG6580 firewall. This feature allows you to set up a separate subnetwork for remote

access from the Internet to your computer, gaming devices, or other IP-enabled device so that your

home network is not exposed to hackers or other external attacks from the Internet. Outside users will

only have direct access to the designated DMZ Host device and not your home network.

If you set up a computer as the DMZ Host, remember to set the IP address back to zero (0) when you are

finished with the needed application, since this computer will be exposed to the Internet. Although the

computer is protected from Denial of Service (DoS) attacks via the SBG6580 firewall, it is still exposed to

the Internet.

Figure 51 – Advanced DMZ Host Screen

Table 17: Advanced DMZ Host-Field Descriptions

Field

Description

DMZ Host

Enter the IP address of the selected computer you are

setting up as the DMZ host.