Reference Guide for the Model RT328 and Model RH348 ISDN Routers
Filter Configuration 8-11
Implementing the Filter
Now you can proceed to define a call filter to block the three NetBIOS service ports.
The Filter Set Configuration Menu is shown in Figure 8-3.
To define a call filter:
1.
Go to Menu 21 - Filter Set Configuration, and choose a name and filter set.
Figure 8-3. Menu 21 Filter Set Configuration
2.
Next, define the filter rules.
You want your filter to ignore (drop) UDP and TCP packets originating from ports 137, 138,
and 139. Because each protocol/port combination must be specified as a separate rule, there
will be six rules. Each filter set contains six rules, so you will fill one entire set. Begin with
rule 1, as illustrated in Figure 8-3.
Menu 21 - Filter Set Configuration
Filter Filter
Set # Comments Set # Comments
------ ----------------- ------ -----------------
1 netbios 7 _______________
2 _______________ 8 _______________
3 _______________ 9 _______________
4 _______________ 10 _______________
5 _______________ 11 _______________
6 _______________ 12 _______________
Enter Filter Set Number to Configure= 1
Edit Comments= netbios
Press ENTER to Confirm or ESC to Cancel:
Filter.fm Page 11 Tuesday, October 10, 2000 3:25 PM