Cabletron Systems Cabletron CyberSWITCH CSX5500 User Manual

Also see for CyberSWITCH 5500: Quick start Manual

Contents

USER’S GUIDE304 CyberSWITCHBecause the Packet Types within the conditions specify both source and destination addressinformation, Global application may often be sufficient to filter IP traffic across the entire system.However, the Input, Output and User-Based application points are defined in case theadministrator needs to apply a finer level of filtering which cannot be obtained on a Global basis.Example: order of execution of filter application pointsApplication to Network InterfacesA forwarding filter is applied to an IP Network Interface through the IP Interface configuration. A filtermay be applied to both the input and output stages of the Network Interface.It is important to note that the Unnumbered WAN Interface which appears in the IP Interfaceconfiguration is simply the enabling condition for operation with unnumbered WAN links. Theactual unnumbered Network Interfaces are created dynamically at run-time, with the name of theremote WAN device providing the unique identifier for the Interface. Consequently, when a filteris applied to the externally visible Unnumbered WAN Interface, it will apply to all dynamicunnumbered interfaces which are created internally at run-time. If it desired to apply a filter to aspecific unnumbered interface, this can be accomplished by applying a User-Based filter.P ACKET T YPESA Packet Type is a set of comparisons which are made against the contents of an IP packet. It is thefundamental element of an IP filter condition. For a match to occur, ALL the constituentcomparisons must yield a TRUE result. The type is composed of a common packet portion whichspecifies fields in the IP header, and a protocol-specific portion which references the upper- layerprotocol fields and is dependent upon which Protocol field of the IP Header, if any, is used as acriterion.OUTPUTUSERINPUTUSERNetwork Interface Network InterfaceGLOBALIP Routing ProcessCONNECTIONFilter Application PointsFilter Execution Order