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Port Forwarding

Use the Port Forwarding menu to create Virtual Server functions through the Router. A Virtual

Server can allow remote users to access services on your LAN such as FTP for file transfers or

SMTP and POP3 for e-mail. The DSL-504T will accept remote requests for these services at your

Global IP Address, using the specified TCP or UDP protocol and port number, and then redirect

these requests to the server on your LAN with the Private IP address you specify. Remember that

the Private IP Address must be within the range specified for your LAN.

The Virtual Server feature employs UDP/TCP port redirection to direct traffic through the WAN port

to specified servers on your private network. Port redirection can also be used to direct potentially

hazardous packets to a proxy server outside your firewall. For example, you can configure the

Router to direct HTTP packets to a designated HTTP server in the DMZ. You can define a set of

instructions for a specific incoming port or for a range of incoming ports. Each instruction set or

rule is indexed and can be modified or deleted later as needed.

Virtual server configuration sets can be used together with complimentary features such as Firewall

Rules, DMZ devices and IP Filters to improve efficiency and security. Consider how these other

functions will effect the virtual server sets you have configured and enabled.

The table below describes the configuration settings presented in the Virtual Server menu.

Virtual Server Menu and List

To modify virtual server settings for any previously created virtual server set listed, click on the

note pad icon in the right hand column of the

Virtual Servers List

for the set you want to

configure. The set will appear highlighted in the list and the parameters that have been configured

appear in the settings fields above the list. Adjust the settings as desired and click the

Apply

button to put them into effect.

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To configure a virtual server set, define the following settings in the Virtual Server configuration

menu located in the top half of the browser window.

Parameter

Description

Rule Name

Provide a name for the rule. This name will not appear in the list

below, however it may be useful if you later need to edit the

settings for the rule. Rule names are optional.

Private IP

This is the IP address of the server on your LAN that will provide

the service to remote users. The Private IP address is used to

direct the service to a specific computer on your private network

such as an FTP, Email or public web server. Type in the IP

address of the server used for the service being configured here.

Protocol

You can select the transport protocol (TCP or UDP) that the

application on the virtual server will use for its connections.

Select one of the following options from the pull-down menu to

define a

TCP

,

UDP

or

Both

. The choice of this protocol is

dependent on the application that is providing the service.

If you

do not know which protocol to choose, check your application

’

s

documentation.

Port Start /Port End

Configure a range of ports for forwarding. Type the lowest

numbered port in the range in the Port Start space. Type the

highest numbered port in the Port End space. For a single port,

just enter the same number in both spaces.

Virtual server port redirection must be used with a specified

server or computer on the LAN (identified by the Private IP

address).

Port Map

This is the local port being forwarded to from the Port Start/Port

End port(s). Keep in mind that if you use a non-standard port

number for an application with a reserved UDP/TCP port, some

additional configuration may be required for the servers or

workstations using the application on the LAN side.

Click the

Apply

button to put the new virtual server configuration set or modification into effect.

Any server sets configured in the menu will appear in the Virtual Server List with the new settings.

The Router must save the new settings and reboot before the new virtual server configurations are

applied.

To remove any configuration set from the Virtual Server List, click on the trashcan icon for set you

want to delete.

Note

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DMZ

Since some applications are not compatible with NAT, the Router supports use of a DMZ IP address

for a single host on the LAN. This IP address is not protected by NAT and will therefore be visible to

agents on the Internet with the right type of software. Keep in mind that any client PC in the DMZ

will be exposed to various types of security risks. If you use the DMZ, take measures (such as

client-based virus protection) to protect the remaining client PCs on your LAN from possible

contamination through the DMZ.

DMZ IP address configuration

To designate a DMZ IP address, select the

Enabled

radio button, type in the

IP Address

of the

server or device on your LAN, and click the

Apply

button. To remove DMZ status from the

designated IP address, select the Disabled radio button and click Apply. It will be necessary to save

the settings and reboot the Router before the DMZ is activated.

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Filters

Filter rules in the Router are put in place to allow or block specified traffic. The Filter Rules however

can be used in a single direction to examine and then Allow or Deny traffic for Inbound (WAN to

LAN) or Outbound (LAN to WAN) routed data. The rules based on IP address and TCP/UDP port.

Configure the filter rules as desired and click the

Apply

button to create the rule. The newly

created rule appears listed in the Outbound Filter List at the bottom of the menu. The table below

describes the various parameters that are configured for the filter rules.

Filters Configuration Menu

To modify any previously created filter rule, click on the note pad icon in the right hand column of

the Filter List for the set you want to configure. Adjust the settings as desired and click the

Apply

button to put the new settings into effect.

First determine the direction of the traffic you want the rule to filter. To filter WAN to LAN traffic,

select the

Inbound Filter

option. Any new Inbound Filter rules created will appear in the list.

Likewise, should you to filter LAN to WAN traffic, create an

Outbound Filter

rule.

Note

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The parameters described below are used to set up filter rules.

Parameter

Description

Source IP

For an Outbound Filter, this is the IP address or IP addresses on your LAN

for which you are creating the filter rule. For an Inbound Filter, this is the

IP address or IP addresses for which you are creating the filter rule. You

can opt to indicate a

Mask Range

, a

Single IP

, an

IP Range

or

Any IP

from

the pull-down menu. Choosing Any IP will apply the rule to all WAN or all

LAN IP addresses depending on which type of rule (Inbound or Outbound)

is being configured.

Destination IP

Where the Destination IP address resides also depends on if you are

configuring an Inbound or Outbound filter rule. You can opt to indicate a

Mask Range

, a

Single IP

, an

IP Range

or

Any IP

from the pull-down menu.

Source Port

The Source Port is the TCP/UDP port on either the LAN or WAN depending

on if you are configuring an Outbound or Inbound Filter rule. Select one of

the following options from the pull-down menu to define a

Any Port, Single

Port

,

Port Range

or

Safe Range

(ports above 1024).

Destination Port

The Destination Port is the TCP/UDP port on either the LAN or WAN

depending on if you are configuring an Outbound or Inbound Filter rule.

Select one of the following options from the pull-down menu to define a

Any Port, Single Port

,

Port Range

or

Safe Range

(ports above 1024).

Protocol

Select the transport protocol (

TCP

,

UDP

or

All

) that will be used for the

filter rule.

Action

Select to

Allow

or

Deny

transport of the data packets according to the

criteria defined in the rule. Packets that are allowed are routed to their

destination; packets that are denied are blocked.

Click the

Apply

button to put the new rule into effect. Any filter rule configured in the menu will

appear in the Filters List with the new settings. The Router must save the new settings and reboot

before the new rules are applied.