ZyXEL Communications NBG420N User Manual

 Chapter 13 Firewall

NBG420N User’s Guide

Available Services This is a list of pre-defined services (ports) you may prohibit your LAN computers 

from using. Select the port you want to block using the drop-down list and click 

Add to add the port to the Blocked Services field.

Blocked Services

This is a list of services (ports) that will be inaccessible to computers on your LAN 

once you enable service blocking. 

Custom Port

A custom port is a service that is not available in the pre-defined Available 

Services list and you must define using the next two fields.

Type

Choose the IP port (TCP or UDP) that defines your customized port from the drop 

down list box.

Port Number

Enter the port number range that defines the service. For example, if you want to 

define the Gnutella service, then select TCP type and enter a port range from 

6345 to 6349.

Add

Select a service from the Available Services drop-down list and then click Add to 

add a service to the Blocked Services

Delete

Select a service from the Blocked Services list and then click Delete to remove 

this service from the list.

Clear All

Click Clear All to empty the Blocked Services.

Schedule to Block

Day to Block:

Select a check box to configure which days of the week (or everyday) you want 

service blocking to be active. 

Time of Day to 

Block (24-Hour 

Format)

Select the time of day you want service blocking to take effect. Configure blocking 

to take effect all day by selecting All Day. You can also configure specific times by 

selecting From and entering the start time in the Start (hour) and Start (min) 

fields and the end time in the End (hour) and End (min) fields. Enter times in 24-

hour format, for example, "3:00pm" should be entered as "15:00".

Log

Active (Log 

packets match 

this rule)

Select this to log packets that match this rule. Go to the Log Settings page and 

select the Access Control logs category to have the NBG420N record these logs.

Misc setting

Bypass Triangle 

Route

Select this check box to have the NBG420N firewall ignore the use of triangle 

route topology on the network. 

Max NAT/Firewall 

Session Per User

Type a number ranging from 1 to 2048 to limit the number of NAT/firewall sessions 

that a host can create.

Apply

Click Apply to save the settings. 

Reset

Click Reset to start configuring this screen again. 

Cancel

Click Cancel to return to the Services screen without saving any changes.

Table 59   Security > Firewall > Services > Adding a Rule