User's Manual

Reference Manual for the Model DG834G Wireless ADSL Firewall Router
Protecting Your Network 5-9
• Local computers must access the local server using the computer’s local LAN address
(192.168.0.11 in the example in Figure 5-6 above). Attempts by local computers to access the
server using the external WAN IP address will fail.
Outbound Rules (Service Blocking)
The DG834G allows you to block the use of certain Internet services by computers on your
network. This is called service blocking or port filtering. You can define an outbound rule to block
Internet access from a local computer based on:
• IP address of the local computer (source address)
• IP address of the Internet site being contacted (destination address)
•Time of day
• Type of service being requested (service port number)
Following is an application example of outbound rules:
Outbound Rule Example: Blocking Instant Messenger
If you want to block Instant Messenger usage by employees during working hours, you can create
an outbound rule to block that application from any internal IP address to any external address
according to the schedule that you have created in the Schedule menu. You can also have the router
log any attempt to use Instant Messenger during that blocked period.
Figure 5-7: Rule example: Blocking Instant Messenger