Bridging And Routing Protocol Filtering - Cabletron Systems CyberSWITCH CSX400 Installation Manual

Chapter 2: About the CSX400
The CSX400 supports the IEEE 802.1d standard for LAN to LAN
IEEE 802.1d Bridging —
bridging. Bridging is provided over PPP and Frame Relay as well as adjacent LAN ports. The
bridging software uses transparent bridging. When the CSX400 is configured as a bridge, the unit
bridges data packets to the destination, regardless of the network protocols used. The CSX400 uses
the Spanning Tree Algorithm to provide bridging redundancy while preventing data loops and
duplicate data. This is a self-learning bridge, i.e., the bridge builds and updates an address table
with each MAC source address and associated information when the packets are received.
IP Routing — IP routing support provides the ability to process TCP/IP frames at the network
layer for routing. IP routing support includes the Routing Information Protocol (RIP) that allows
the exchange of routing information on a TCP/IP network. The CSX400 receives and broadcasts
RIP messages to adjacent routers and workstations.
Internet Packet Exchange (IPX) routing support provides the ability to process
IPX Routing —
Novell proprietary frames at the network layer for routing. IPX routing support includes both
Routing Information Protocol (RIP) and Service Advertising Protocol (SAP) that allows the
exchange of routing information on a Novell NetWare network. The SAP provides routers and
servers containing SAP agents with a means of exchanging internetwork service information.

Bridging and Routing Protocol Filtering

Filtering is used to allow efficient usage of network resources and provide security for your
network and hosts.
The CSX400 supports IP Internet Firewall filtering to prevent
IP Internet Firewall —
unauthorized access to your system and network resources from the Internet or a corporate
Intranet. Security can be configured to permit or deny IP traffic. The security is established by
configuring IP access filters, which are based on source IP address, source mask, destination IP
address, destination mask, protocol type, and application port identifiers for both Transmission
Control Protocol (TCP) and User Datagram Protocol (UDP) protocols. These IP access filters
allow individual IP source and destination pair filtering as well as IP address ranges and wild
carding to match any IP address. These Firewall filters can be defined to allow inbound only,
outbound only, or bi-directional IP communication up to the UDP and TCP application port level.
Firewall access filters provide a lot of flexibility to establish a powerful IP security barrier. The
CSX400 supports the IP Access Control (from the ctip-mib) Internet Firewall Filter.
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