ZyXEL Communications Prestige 2602HWL-D3A Support Manual page 56

A filter for blocking the NetBIOS packets

Introduction
The NETBIOS protocol is used to share a Microsoft comupter of a workgroup. For the security concern, the
NetBIOS connection to a outside host is blocked by Prestige router as factory defaults. Users can remove the
filter sets applied to menu 3.1 and menu 4.1 for activating the NetBIOS services. The details of the filter
settings are described as follows.

Configuration
The packets need to be blocked are as follows. Please configure two filter sets with 4 and 2 rules respectively
based on the following packets in SMT menu 21.
Filter Set 1:
o Rule 1-Destination port number 137 with protocol number 6 (TCP)
o Rule 2-Destination port number 137 with protocol number 17 (UDP)
o Rule 3-Destination port number 138 with protocol number 6 (TCP)
o Rule 4-Destination port number 138 with protocol number 17 (UDP)
o Rule 5-Destination port number 139 with protocol number 6 (TCP)
o Rule 6-Destination port number 139 with protocol number 17 (UDP)
Filter Set 2:
o Rule 1-Source port number 137, Destination port number 53 with protocol number 6
(TCP)
o Rule 2-Source port number 137, Destination port number 53 with protocol number 17
(UDP)
Before starting to set the filter rules, please enter a name for each filter set in the 'Comments' field first.
Filter
Menu 21 - Filter Set Configuration
Filter
All contents copyright (c) 2007 ZyXEL Communications Corporation.
Prestige 2602HWL-D3A Support Notes
56