ELSA LANCOM Business LC-4X00 Manual page 73

Suitable filters are therefore required. These enable you to exclude from transmission
over the WAN or at least restrict data packets which are only used in internal network
communications, for example:
Propagated frames
These special data packets use protocols which cannot in fact be routed. This data
is encapsulated in normal IPX packets and sent as broadcast so that they can
nevertheless participate in common routing.
These packets are sometimes not desirable in routing. For this reason, you can
specify explicitly whether this type of packet is to be routed or filtered.
Socket filter
Every packet in an IPX network contains destination and source sockets along with
destination and source addresses. Sockets identify the processes for which the
data in the packet is intended.
There is a filter table each for sockets from local and remote networks containing
the filters which can be used to exclude individual or entire groups of destination
sockets. Certain sockets which are known frequently to be the cause of unwanted
connections have already been entered in the socket filter table as default settings.
RIP and SAP information
A router uses the RIPs to inform the other routers of all the routes (paths to the other
networks) known to it using the split horizon principle. This includes the entries
from its own routing table and all routes which the router has derived from other
routers. It gets its information for this purpose from routers on both local and
remote networks. The router enters all available routing information in its internal
RIP table.
The servers offer their services in the SAP information. The various services are
represented within the SAP information as numbers. Each service (e.g. file server
or print server) has a unique number. The router incorporates the information on the
services available in its internal SAP table and registers which service is available
on which network at which MAC address. At the same time it also establishes
whether the service offered is located in a local or remote network and whether it
can propagate the service without first establishing a connection.
You can look at the RIP and SAP tables and their current values in the IPX module
(
setup/IPX-module/RIP-config
RIP and SAP information are extremely important for devices communicating on a
network, which is why there are various different options for setting up the
transmission of these packets.
– A LAN and WAN filter table can be used to tell the router not to include
information on routes to particular networks or on certain available services in
Operating modes and functions
or ) of the router.
SAP-config
ELSA LANCOM Business
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