D-Link DSL-2750U User Manual page 60

Enter the Filter Name and specify at least one of the following criteria: protocol,
source/destination IP address, subnet mask, and source/destination port.
Click Apply to save the settings.
Note:
The settings are only applied when the firewall is enabled.
The ACTIVE INBOUND FILTER shows detailed information about each created
inbound IP filter.
DSL-2750U User Manual
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