Reference Guide for the Model RT328 and Model RH348 ISDN Routers
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
To define a call filter:
1.Go to Menu 21 - Filter Set Configuration, and choose a name and filter set.
| 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:
Figure
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
Filter Configuration |