Bay Technical Associates RM356 Reducing Unnecessary Calls by Windows, Diagnosing the Situation

Reference Guide for the Model RM356 Modem Router

Reducing Unnecessary Calls by Windows 95

One example of when to apply a filter set is reducing unnecessary calls by Windows 95. When using Windows 95 with a dial-up router, you may need to make some configuration changes to avoid having calls placed unnecessarily. Most of these unnecessary calls are caused by PCs on the LAN trying to perform local NetBIOS name resolution, either in response to a user action (browsing the Network Neighborhood or turning a PC on or off, for example) or as periodic background activity. In some cases, this NetBIOS activity can be kept local by other means, such as configuring a WINS or DNS server on the local network, using an LMHOSTS file to store addresses of local hosts, or turning off NetBIOS name resolution by DNS. A simpler method is to filter NetBIOS traffic using the filtering capabilities of your Model RM356 Modem Router.

Diagnosing the Situation

If you already know the source or types of packets that are causing the problem, you can proceed directly to the design of the filter. Otherwise, you can use a sniffer or the router’s built-in tools to determine the source. A particularly useful tool is the display in Menu 24.1 of the “LAN Packet Which Triggered Last Call.” Figure 8-2 illustrates the header of the packet that caused an unwanted call to be placed.

LAN Packet Which Triggered									Last Call: (Type:						IP)
45	00	00	3E	9E	05	00	00	1F	11	CC	9D	8D	FB	17	12	CF	45	BC	B9	00	89 00	35
00	2A	63	C8	01	85	01	00	00	01	00	00	00	00	00	00	0A	53	41	4E	54	41 43	4C

Figure 8-2. LAN Packet Which Triggered Last Call

Filter Configuration 8-9