3Com 812 manual IPX SAP Packet Filtering Using CLI, Bridge / Generic Filtering Using CLI

6-34CHAPTER 6: MANUAL SETUP

IPX SAP Packet Filtering Using CLI

SAP packets are used to identify the services and addresses of servers attached to the network. The responses are used to update a table in the router known as the Server Information Table.

You define IPX SAP packet filtering rules in the IPX-SAP protocol section of the filter file. You can filter SAP packets by network, node, server, service-type, and socket.

The following rule example accepts SAP services from the server name sales_1, with a socket number is less than 32:

IPX-SAP:

1AND server = sales_1;

2ACCEPT socket < 32;

999DENY;

Bridge / Generic Filtering Using CLI

The rules in this filter file section are setup to allow bridging of only IP and IPX packets (assuming that all traffic is being bridged and that the IPX protocol is using Ethernet_II framing). To stop traffic in both directions, you can apply the filter as an input_filter on both the Ethernet and the WAN or User Profile interfaces. However, to improve efficiency over the WAN interface, it would be better to have the same type of filter applied on the equipment at the other side of the WAN to keep non-IP and IPX traffic off the WAN completely.

BR-ETH:

#Allow IP traffic

1 ACCEPT generic=>origin=FRAME/offset=12/length=2/mask=0xFFFF/value=0x0800;

#Allow ARP traffic

2ACCEPT generic=>origin=FRAME/offset=12/length=2/mask=0xFFFF/value=0x0806;

# Allow IPX traffic

3ACCEPT generic=>origin=FRAME/offset=12/length=2/mask=0xFFFF/value=0x8136;

4ACCEPT generic=>origin=FRAME/offset=12/length=2/mask=0xFFFF/value=0x8137;

999DENY;

Step by Step Guide to	You can create filter files using any text editor. Once the file is created, use the
Creating Filter Files	Trivial File Transfer Protocol (TFTP) to place the filter file in the router FLASH
Using CLI	memory.
	To create a filter file using CLI:

1Open a new text file. Enter the file descriptor on the first line: #filter

2Enter a file section header followed by a colon for the protocol rules you want to define. For example, if you want to define IP filtering rules, enter the following section header: IP: