Packet Filters, Packet Filtering | 3Com 2200 specs

12	CREATING AND USING
	CREATING AND USING
	PACKET FILTERS

	This chapter describes how to create and edit packet ﬁlters using the packet
	ﬁlter language. This chapter also provides instructions for how to:
	■ List, display, and delete currently deﬁned ﬁlters
	■ Load packet ﬁlter deﬁnitions created in an ASCII-based editor onto the
	Switch 2200 system
	■ Assign ﬁlters to ports on the system

About	Independently conﬁgurable packet ﬁltering is provided for the various
Packet Filtering	packet processing paths on each Ethernet port of a Switch 2200. The packet
	processing paths are deﬁned in Table 12-1.
	Table 12-1 Packet Processing Paths

Path	Description

Transmit all	All frames that are transmitted to the segment connected to the port
Transmit	All multicast (including broadcast) frames that are transmitted to the
multicast	segment connected to the port
Receive all	All frames that are received by the port from the segment connected
	to the port
Receive	All multicast (including broadcast) frames that are received by the
multicast	port from the segment connected to the port

When you create a packet ﬁlter, you can assign it to the transmit or the receive path of each port, or to both paths.

For additional detailed explanations of packet ﬁlter concepts, see Chapter 7:

User-deﬁned Packet Filtering in the SuperStack™ II Switch 2200

Operation Guide.

Image 138

3Com 2200 manual Packet Filters, Packet Filtering

Contents

Superstack II Switch Administration Console User Guide 3Com Corporation 5400 Bayfront Plaza Santa Clara, California Contents Setting Up an IP Interface for Management Administration Console Interface ParametersRemote Access Parameters Online Help About Setting Baselines Setting PasswordsRebooting the System Setting Baselines Setting the Aging Time Setting tmaxLowerBoundSetting lerAlarm Setting lerCutoff Starting Port Monitoring 10-8 Setting the Bridge Priority10-7 10-9 Opcodes A-1 Using Groups in Packet Filters Listing Groups13-3 Destination Address Filter A-9 World Wide Web Site 3ComForum on CompuServe Access by ModemSupport from 3Com Returning Products for Repair Familiarity with communications protocols that are used on About this GuideIntroduction Interconnected LANs How to Use Switch 2200. The parts of the guide are described in TableThis Guide Conventions This guide Switch DocumentationDocuments, contact your sales representative for assistance Comments Introduction Administration Overview About Switch AdministrationConﬁguration Tasks General System Commands Task Quick Command For Details, See Adjust the console screen height for your terminal To the system, or reset nonvolatile data to defaults Change the factory default baud rate of the Console port System Management Setup Commands Task Quick Command Bridging Commands Task Quick Command For Details, SeeConfigurations, and spanning tree configurations Display bridge port information Administer bridge port addresses12-1 and following Set the multicast packet firewall threshold Ethernet Commands Task Quick Command For Details, See A summarized or detailed format9-2 to Fddi Commands Task Quick Command 8-3 Access HOW to USEInitial User Access Levels of User Select access level read, write, administer Password Using Menus to Perform Tasks System-level Functions Menu Hierarchy for Administer Access Fddi Menu Bridge Menu Bridging Menu Hierarchy for Administer Access IP Menu Snmp Menu Analyzer Menu Most abbreviated version of the same command string is Menu options are not case sensitive Entering Values Adjusting Console InterfaceParameters Disabling Reboot Abort Keys System consoleLock Running Scripts Administration Console Tasks Setting Timeout Interval for Remote SessionsEnter the telnet timeout interval 30 minutes to 60 minutes HOW to USE the Administration Console Running Scripts of Administration Console Tasks Getting HelpConsole Exiting Exiting returns you to the password promptTo exit from the Administration Console There, by pressing the ESC key SYSTEM-LEVEL Functions Page Access to the System AboutManagement Setting Up Console Serial Port Setting Up an IP Interface for Broadcast Address Directed all 1s in the host field Cost Ports AllBroadcast address Ip interface modify Removing an Interface Gateway IP Address Timing outTimed out Defining a Static Route Default route is immediately removed from the routing table Administering the ARP Cache Setting the RIP Mode Enter the IP address of the station you want to ping You could receive one of the following responses Displaying IP Statistics IP statistics you can view are described in TableStatistics are displayed, as shown in this example Setting Up Snmp on Your System Displaying Snmp SettingsCommunity string settings are displayed as shown here Administering Snmp Trap Reporting Community string length Conﬁguring Trap Reporting Enter an IP address of the Snmp manager destination address This example shows a trap conﬁguration Trap address invalid or unreachable Remote SMT events. On all other Switch 2200s in your network You receive the following prompt Snmp trap smtProxyTraps Example of a Switch 2200 system conﬁguration display EnvironmentDisplaying System Conﬁguration Setting Passwords Initial passwords Setting the System Name Changing the Date and TimeYou are prompted for the name of the system Rebooting Baselines About SettingYou must disable the baseline Displaying the Current Baseline Enabling or Disabling Baselines Setting BaselinesBaselining is automatically enabled when a baseline is set Message similar to the following appears SAVING, RESTORING, and Resetting Nonvolatile Data Working withNonvolatile Data Saving NV Data Saving the NV data RestoringNV Data Restoration rules described here System nvData restore Examining a Saved NV Data File You are returned to the NV data menu options Resetting NV Data to Defaults You see the following prompt III Ethernet and Fddi ParametersPage Ethernet Port PortsDisplaying Information RxDiscards Describes the information provided about an Ethernet port Long and are not configurable Default is enabledLayer to receive them or because the port was disabled Disabled Transmitted successfully Second long and are not configurableSuccessfully TxPeakByteRate There is no buffer space available Frame is in error TxDiscards TxQOverflows TxFrames Frames delivered to this port Setting the Port State Labeling a Port Administering ResourcesFddi Stations ConnectPolicy Describes these statisticsCan be Thru, Isolated, WrapA, and WrapB This value can be user-defined Frames NIF. This value can be user-defined Defaults for connecting to a Port MDescription of Fields for Fddi Station Attributes TNotify TraceMaxExp Topology With defaults for connecting to a Port MNormal tree connection Node may not go to Thru state in CFM Setting Neighbor Notiﬁcation Timer Enabling Disabling Status Reporting Fddi Paths TmaxLowBound Description of Fields for Fddi Path Attributes MaxTReqRingLatency TraceStatus Current Trace status of the path TvxLowBound To set tvxLowerBound Station, which appears in brackets Fddi MACs Displaying MAC Information Administering Fddi MACs Describes the information provided for the Fddi MAC Neighbor Error during receptionDescription of Fields for Fddi MAC Attributes OldDownstream OldUpstream There is no buffer space available Frame is in error Receive Frame Network Setting the Frame Error Threshold Shows the order in which the discard tests are made Setting the Not Copied Threshold Enter the new threshold value. See the following example Enabling Disabling LLC Service Setting MAC Paths Administering Fddi Ports Displaying Port Information Describes the type of information provided for an Fddi port Setting lerCutoff Setting Port Labels Fddi port path Roving Analysis About RovingAnalysis Roving Analysis On a speciﬁc systemReceive Adding an Analyzer Port Removing an Analyzer Port You can start monitoring port activity Starting PortMonitoring See the example below for starting port monitoring Stopping Port Monitoring Bridging Parameters Displaying Bridge Information Information about the bridge is displayed Following example shows a display of bridge information Each item in the bridge parameter list is described in Table Root. The default value is 2 seconds BridgeFwdDelayLearning states. The default value is 15 seconds ForwardDelay Is determined by the root bridge Default value is disabledBridge Attributes Parameter Description MaxAge Mode Fragmentation EnablingDisabling IP Disabling IPX Threshold SettingAddress Aging Time Enter enabled or disabled at the prompt STP BridgeEnabling and Disabling STP on a Bridge Setting the Bridge Maximum Age To conﬁgure the STP bridge priority Forward delay The recommended value is 15 seconds To conﬁgure the forward delay value Setting the STP Group Address Bridge Port Following example shows a bridge port summary display Following example shows a bridge port detail display DesignatedCost RxErrorDiscsPort is attached BPDUs from the designated bridge for that LAN RxMcastExcDiscs Bridge Port Attributes Parameter Description RxFramesManagement frames Exceeded Bridge Port Attributes Parameter Description State Disabled in which the port is currently operatingDisabled The port has been disabled by management Blocking The bridge continues to run the Spanning Tree Shows the order in which the discard decisions are made Multicast Limit You are prompted for port typeMulticast packet ﬁrewall, see Bridging Extensions Disabling STP STP Bridge PortEnabling On a Port Bridge port stpCost Bridge port stpPriority Administering Port Addresses Listing Addresses Enter the number of the port From the top level of the Administration Console, enterYou are prompted for the port number You are prompted for one or more addresses to add Flushing All Addresses You are prompted for the port numbers Packet Filters Packet Filtering Listing Packet Filters Displaying Packet Filters Creating and Using Packet Filters Describes the instructions and stacks of a packet ﬁlter Basic Elements of a Packet Filter Ethernet and Fddi Packet Fields Size of the field can be 1, 2, 4, or 6 bytes Packet Filter Operands Description Opcode Packet fieldPushField Want the filter to examine a 48-bit address Constant Accept and Reject Instructions Preprocessed and Run-time Storage Creating Packet Filters 12-9 Opcode.size operand... # comment 12-11 Creating and Using Packet Filters Pseudocode translates into the following packet ﬁlter # XNS Filtering Section Enter executable instruction #1 Enter executable instruction #2 Enter executable instruction #5 Enter executable instruction #3Enter executable instruction #4 Enter executable instruction #6 This combination looks like this Only IP pkts w/in socket range Add a not statement to discard any matching packets Maximum length of a packet ﬁlter deﬁnition is 4096 bytes Delete Previous Ctrl+h Command are discardedBeing edited Character One position Delete Current Ctrl+d Saving Deleting Packet FiltersEditing, Checking Packet Filters At the Replace existing filter? prompt Loading Packet Filters Bridge packetFilter load Fddi Unassigning Packet Filters from Ports User-deﬁned Packet Filtering in the SuperStack II Switch Configuring Address Port Groups to USE Packet FiltersUsing Groups Address and port groups in packet ﬁlters OR, for port groups, enter the following command To list the currently deﬁned groups, enter this command Enter this command Displaying Groups Creating New Groups Enter the ports in this syntax Address 08-32-45-e3-32-21 Port Ethernet Adding AddressesPorts to Groups Address 08-37-21-65-78-c4 OR, to remove a port from a group, enter Removing Addresses or Ports from a GroupTo remove an address from a group, enter Enter the ports in the syntax Address 08-42-21-84-78-f1 Loading Groups 13-11 Configuring Address and Port Groups to USE in Packet Filters Appendixes Opcodes are described in this section Packet Filter OpcodesOpcodes Name name PushField.size offset Bytes PushLiteral.size value Byte PushDAGM PushTopByte PushSAGM Byte PushSPGM Byte PushDPGMByte Eq equal Ne not equal Byte Lt less thanByte Le less than or equal to Gt greater than Byte Ge greater than or equal toByte Bit-wise Byte Not Or bit-wise orByte Xor bit-wise exclusive-OR Byte Accept Reject Byte Shiftl shift leftByte Shiftr shift right Packet Filter ExamplesPacket ﬁlter concepts Address To make a copy of the type ﬁeld XNSPage Errors Common Syntax Hexadecimal Characters of the numberNumber with a leading 0x or 0X is treated as Number with a leading 0 is treated as octal Online Technical ServicesVariety of services. This appendix describes these services Through the following online systems Access by Isdn Press Return to see the 3ComForum main menu Your Network Maintenance, application training, and support servicesSupport from Supplier 3Com U.S. and Canada, call 800 876-3266 for customer serviceTo ﬁnd your authorized service provider Support contracts are available from 3Com 3ComFacts B-3 3ComForum B-2 Abort Address Resolution Protocol. See ARP address thresholdIndex ARP cache ﬂushing 3-12 removing entry Multicast limit, setting 11-7 Spanning Tree Enabling Statistics, displaying 10-1bridge portCost Fddi path deﬁned SRFs 8-2 Connection policies, settingPortState Station MAC addresses 11-11Ethernet address Fddi port Removing from -9, 3-10 status Enabling Le opcode A-5 Password conﬁguring Name opcode A-1 Naming the Switch 2200 4-3ne opcode A-5On-line technical services B-1opcode Multicast frames Packet ﬁlters 12-1multicast limit Broadcast address 3-4default mode 3-12displaying state RloginFddi ports 8-19ping IP station Snifﬁng. See roving analysis and analyzer Snmp agent Accessing through IP 3-1deﬁned Snmp trapSMT event Port LER Condition Port Path Change TOpr Technical support B-1telnet SwitchDeﬁned 8-7 setting Packet ﬁlter 12-12, 12-14, A-11 xor opcode A-7