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61

SNTP

Simple network timing protocol (SNTP) is a protocol used to synchronize the system time to

public SNTP servers. It uses the UDP protocol on port 123 to communicate between clients and

servers. The 6381 supports SNTP client functionality in compliance with IETF RFC 2030. The

system clock time in the 6381 can be configured to send client requests to the configured SNTP

server addresses periodically.

The main function of the Simple Network Time Protocol (SNTP) is to provide the network with a

precise time based on Internet standards. Enter the information of the SNTP server to which you

will be connecting.

To configure SNTP:

1.

From the navigation bar at the top of the screen click

Advanced

2.

From the left hand navigation pane select

SNTP

.

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62

3.

Check

Enable SNTP.

4.

Specify one or more SNTP servers in the

Primary SNTP Server

,

Secondary SNTP Server

,

and

Tertiary SNTP Server

fields and the SNTP options.

Primary SNTP Server

The IP address or the host name of the primary SNTP server. This IP

address can be provided by ISP or user-defined.

Secondary SNTP

Server

The IP address or the host name of the secondary SNTP server. This IP

address can be provided by ISP or user-defined.

Tertiary SNTP Server

The IP address or the host name of the tertiary SNTP server. This IP

address can be provided by ISP or user-defined.

Timeout

If the RG failed to connect to a SNTP server within the Timeout period, it

retries the connection.

Polling Interval

The amount of time between a successful connection with a SNTP server

and a new attempt to connect to an SNTP server.

Retry Count

The number of times the RG tries to connect to an SNTP server before it

tries to connect to the next server in line.

Time Zone

The time zone in which the RG resides.

Day Light

Check/uncheck this option to enable/disable daylight saving time (DST).

Note: DST is not automatically enabled or disabled. You need to manually

enable and disable it.

5.

Click

Apply

The Apply button will temporarily save this connection. To make the change permanent, click

Tools

(at the top of the page) and select

System Commands

. On the

System Commands

page, click

Save All

.

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63

Port Forwarding

The port forwarding (or virtual server) feature allows you to direct incoming traffic to specific LAN

hosts based on a protocol port number and protocol. Using the Port Forwarding page, you can

provide local services (for example web hosting) for people on the Internet or play Internet

games. When users send this type of request to your network via the Internet, the modem will

forward those requests to the appropriate PC. Port forwarding can be used with DHCP assigned

addresses but remember that a DHCP address is dynamic (not static). For example, if you were

configuring a NetMeeting server, you would want to assign this server a static IP address so that

the IP address is not reassigned. Also remember that if an Internet user is trying to access an

Internet application, they must use the WAN IP address. The port forwarding will translate the

WAN IP address into a LAN IP address.

NOTE:

To configure a port you must have an existing LAN client with an IP address. You can add

a LAN client on the

LAN Clients

page.

A database of predefined port forwarding rules allows you to apply one or more rules to one or

more members of a defined LAN group. You can view the rules associated with a predefined

category and add the available rules for a given category. You can also create, edit, or delete

your own port forwarding rules.

To configure a service, game, or other application:

1.

From the navigation bar at the top of the screen click

Advanced

2.

From the left hand navigation pane select

Port Forwarding

.

3.

From the

WAN Connection

dropdown select the external connection.

If the desired LAN IP is not available in the LAN IP drop-down menu, you can add it using

the LAN Client page, which is accessed by clicking

New IP

. See LAN Clients on page 72.

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64

Port Forwarding Fields:

WAN Connection

Select the WAN connection to which port forwarding is applied.

Select LAN Group

Select the LAN Group to which port forwarding is applied.

LAN IP

Select the IP address to host the service.

Allow Incoming

Ping

Enabling incoming ping (ICMP) requests on the Port Forwarding page allows

the RG to respond to a ping from the Internet.

DMZ

Demilitarized zone. By setting a PC on your local network as demilitarized

zone (DMZ), you can choose to forward all incoming packets that cannot be

routed to a specific IP address to the PC with the DMZ IP address. This

opens the access to the DMZ host from the Internet. This function is disabled

by default. By enabling DMZ, you add an extra layer of security protection for

hosts behind the firewall.

Custom Port

Forwarding

This link takes you to the

Custom Port Forwarding

page.

Category

Custom and user-defined categories.

Available Rules

Predefined and user-defined IP filtering rules for each category.

Applied Rules

Lists the IP filtering rules you elect to apply for each given category.

4.

Select the available rules for a given category and click

Add

to apply the rule for the

category.

You can view a rule associated with a predefined filter on the

Rule Management

page. You

get to the rule management page by selecting a rule from the list in the

Available Rules

pane, then clicking

View

.

5.

To add a custom application, select the User category, click

New

and fill in the port,

protocols and description for your application.

The

New

,

View

, and

Delete

buttons become available only when the

User

category is

selected. All the custom rules you create fall under the

User

Category.

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65

The Rule Management page populates for you to create new rules. Enter

Rule Name

,

Protocol

,

Port Start

,

Port End

, and

Port Map

fields, and then click

Apply

.

6.

Continue to add rules as they apply from each category.

7.

Click

Apply

The

Apply

button will temporarily save this connection. To make the change permanent,

click

Tools

(at the top of the page) and select

System Commands

. On the

System

Commands

page, click

Save All

.