Netopia R7200 manual Broadcasts, Packet header types

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Understanding IP Addressing B-13

The following diagram illustrates the IP address space taken up by the two remote IP subnets. You can see from the diagram why the term nested is appropriate for describing these subnets.

valid addresses used by a.b.c.128

valid addresses used by a.b.c.248

1

129

190

249

254

Address range available to a.b.c.0, less the two nested subnets

Broadcasts

As mentioned earlier, binary IP host or subnet addresses composed entirely of ones or zeros are reserved for broadcasting. A broadcast packet is a packet that is to be delivered to every host on the network if both the host address and the subnet address are all ones or all zeros, or to every host on the subnetwork if the host address is all ones or all zeros but the subnet address is a combination or zeros and ones. Instead of making many copies of the packet, individually addressed to different hosts, all the host machines know to pay attention to broadcast packets, as well as to packets addressed to their speciﬁc individual host addresses. Depending on the age and type of IP equipment you use, broadcasts will be addressed using either all zeros or all ones, but not both. If your network requires zeros broadcasting, you must conﬁgure this through SNMP.

Packet header types

As previously mentioned, IP works with other protocols to allow communication over IP networks. When IP is used on an Ethernet network, IP works with the Ethernet or 802.3 framing standards, among other protocols. These two protocols specify two different ways to organize the very ﬁrst signals in the sequence of electrical signals that make up an IP packet travelling over Ethernet. By default, the Netopia R7200 uses Ethernet packet headers for IP trafﬁc. If your network requires 802.3 IP framing, you must conﬁgure this through SNMP.

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Contents Netopia R7200 Sdsl Router Part Number Contents Part II Advanced Configuration Contents Aurp Snmp Xmodem Part III Appendixes User’s Reference Guide Part I Getting Started User’s Reference Guide Features and capabilities Chapter IntroductionOverview How to use this guide Finding an Internet service provider Chapter Setting Up Internet ServicesEndorsements Deciding on an ISP account Setting up a Netopia R7200 account Obtaining an IP addressUnique requirements Pricing and supportWithout Network Address Translation Obtaining information from the ISPLocal LAN IP address information to obtain With Network Address TranslationUser’s Reference Guide Find a location Chapter Making the Physical ConnectionsWhat you need Identify the connectors and attach the cablesYour router on Netopia R7200 Sdsl Router back panel portsNetopia R7200 LED front panel Netopia R7200 Sdsl Router status lightsReadying computers on your local network Chapter Connecting to Your Local Area NetworkUser’s Reference Guide Connecting to an Ethernet network 10Base-T Adding an external modem Connecting to a LocalTalk network Chapter Setting up your Router with the SmartStart Wizard Before running SmartStart SmartStart Wizard conﬁguration screens Setting up your Router with the SmartStart WizardEasy option Advanced setupAdvanced option Conﬁguration screen on Conﬁguration tab Dynamic conﬁguration recommendedStatic conﬁguration optional Add. Repeat this process for the secondary DNS TCP/IP Conﬁguring TCP/IP on Macintosh computersTCP/IP or MacTCP Dynamic conﬁguration using MacIP optional Setting up your Router with the SmartStart Wizard User’s Reference Guide Chapter Console-Based Management Connecting through a Telnet session Conﬁguring Telnet software Connecting a console cable to your routerPC ANSI-BBS Navigating through the console screensChapter Easy Setup Easy Setup console screensAccessing the Easy Setup console screens See Appendix A, Troubleshooting, for more suggestions Quick Easy Setup connection path Main Menu appears Sdsl Line ConﬁgurationPrevious Screen Next Screen Easy Setup ProﬁleIP Easy Setup Easy Setup Security Conﬁguration Previous Screen To Main Menu Part II Advanced Configuration User’s Reference Guide WAN conﬁguration Chapter WAN and System ConfigurationATM VPI ATM VCI Creating a new Connection Proﬁle IPX Profile Parameters Remote IPX Network Datalink PPP/MP Options Data Compression Default proﬁle Main Menu Default Proﬁle screen appears IP parameters default proﬁle screen System conﬁguration screens IPX parameters default proﬁle screenNavigating through the system conﬁguration screens System conﬁguration features Date and time Network protocols setupFilter sets ﬁrewalls IP address servingConsole conﬁguration Logging Upgrade feature setSnmp Simple Network Management Protocol SecurityInstalling the Syslog client User’s Reference Guide Chapter Line Backup Backup Conﬁguration screen appears Atdt Backup Conﬁguration screenIP Setup screen Connection Proﬁles Using Scheduled Connections with BackupScheduled Connections screen appears Management/Statistics Force Recovery QuickView Event LogsSnmp Support User’s Reference Guide Network Address Translation features Chapter IP Setup and Network Address TranslationHOW NAT Works Previous Screen Using Network Address TranslationV2 multicast Numbered Sdsl WAN1 Associating port numbers with nodesAdvanced IP/IPX router conﬁguration options Data Link Options IP Setup and Network Address Translation Network Address Translation guidelines IP setup User’s Reference Guide Select Add Export. The Add Exported Service screen appears Select Service. a pop-up menu of services and ports appears IP subnets User’s Reference Guide Static routes Viewing static routes Static Routes screen will appearAdding a static route Rules of static route installation Modifying a static routeDeleting a static route Main Menu System Configuration IP Address Serving 176.163.222.10 Dhcp NetBios Options Serve Bootp Clients IP Address Pools IP Setup and Network Address Translation Dhcp NetBIOS Options NetBios Type MacIP KIP forwarding setup You have ﬁnished your IP setup User’s Reference Guide Internetwork Packet Exchange IPX Chapter IPX SetupIPX features IPX deﬁnitionsRouting Information Protocol RIP Service Advertising Protocol SAPIPX address SocketNetBIOS IPX setup screenIPX spooﬁng Default Gateway Address IPX routing tables User’s Reference Guide Chapter AppleTalk Setup AppleTalk networksAppleTalk protocol AT Routing Table Routers and seeding MacIPInstalling AppleTalk Upgrade Feature Set Conﬁguring AppleTalk EtherTalk setupLocalTalk setup Aurp setup Viewing Aurp partnersAurp Free Trade Zone Modifying an Aurp partner Adding an Aurp partnerDeleting an Aurp partner Receiving Aurp connectionsConﬁguring Aurp Options Aurp Options Tickle Interval Hhmmss User’s Reference Guide Quick View status overview Chapter Monitoring ToolsGeneral status Status lights Current statusGeneral Statistics Statistics & LogsEvent histories Physical InterfaceNetwork Interface WAN Event History Device Event History Routing tablesIP routing table IPX routing table IPX Sap Bindery tableAppleTalk routing table Served IP Addresses IP Address Lease Management screen appears Snmp System InformationCommunity strings Snmp Setup screenSnmp traps Deleting IP trap receivers Setting the IP trap receiversViewing IP trap receivers Modifying IP trap receiversWeb-based management pages Event History pages WAN Event History Device Event History User’s Reference Guide Chapter Security Suggested security measuresUser accounts Protecting the conﬁguration screens Protecting the Security Options screenDial-in console access What’s a ﬁlter and what’s a ﬁlter set? Enable SmartStart/SmartView/Web serverTelnet access About ﬁlters and ﬁlter setsFilter priority How ﬁlter sets workHow individual ﬁlters work ﬁltering rule Parts of a ﬁlterPort numbers Other ﬁlter attributes Port number comparisonsUDP Putting the parts togetherFiltering example #2 Filtering example #1Disadvantages of ﬁlters Design guidelinesWorking with IP ﬁlters and ﬁlter sets An approach to using ﬁltersNaming a new ﬁlter set Adding a ﬁlter setAdding ﬁlters to a ﬁlter set Input and output ﬁlters-source and destinationADD this Filter NOW Cancel Deleting ﬁlters Viewing ﬁlter setsViewing ﬁlters Modifying ﬁltersModifying ﬁlter sets Deleting a ﬁlter setSample IP ﬁlter set TCP Icmp UDP Possible modiﬁcations User’s Reference Guide IPX ﬁlters IPX packet ﬁlters Viewing and modifying packet ﬁltersAdding a packet ﬁlter Adding a packet ﬁlter set IPX packet ﬁlter setsDeleting a packet ﬁlter Viewing and modifying packet ﬁlter setsNo Match IPX SAP ﬁlters Deleting a packet ﬁlter setViewing and modifying SAP ﬁlters Deleting a SAP ﬁlter Adding a SAP ﬁlterIPX SAP ﬁlter sets Viewing and modifying SAP ﬁlter setsAdding a SAP ﬁlter set Deleting a SAP ﬁlter set Firewall tutorial General ﬁrewall terms Basic IP packet componentsBasic protocol types Firewall design rules Example TCP/UDP PortsFirewall Logic Logical and function Binary representationImplied rules Established connectionsExample IP ﬁlter set screen Example network Filter basicsExample Example ﬁltersExample Example Chapter Utilities and Diagnostics Ping Receive return Ping packet Stop Ping Trace RouteTelnet client Disconnect Telnet console session Factory defaultsUpdating ﬁrmware Transferring conﬁguration and ﬁrmware ﬁles with TftpDownloading conﬁguration ﬁles Transferring conﬁguration and ﬁrmware ﬁles with Xmodem Uploading conﬁguration ﬁlesIdle Do you want to send a saved configuration to your Netopia? Restarting the system Part III Appendixes User’s Reference Guide Conﬁguration problems Appendix a TroubleshootingNetwork problems Console connection problemsPower outages How to reset the router to factory defaultsEnvironment proﬁle How to reach usTechnical support Before contacting NetopiaFAX-Back Online product informationUser’s Reference Guide What is IP? Appendix B Understanding IP AddressingAbout IP addressing Subnets and subnet masks Subnet masks Example Using subnets on a Class C IP internetISP Network Network conﬁgurationExample Working with a Class C subnet Distributing IP addressesBackground Technical note on subnet masking Netopia R7200 Dhcp server characteristics ConﬁgurationDhcp address serving Serve dynamic WAN clients Using address servingManually distributing IP addresses MacIP servingUnderstanding IP Addressing B-9 Tips and rules for distributing IP addressesDhcp example Internet Nested IP subnets0.0 C.1 WAN 3719 Packet header types BroadcastsUser’s Reference Guide Appendix C Understanding Netopia NAT Behavior Network conﬁgurationBackground User’s Reference Guide Understanding Netopia NAT Behavior C-3 Netopia Router WWW Server ISP Router LAN Understanding Netopia NAT Behavior C-5 Exported servicesImportant notes Understanding Netopia NAT Behavior C-7 Summary Appendix D Binary Conversion Table Decimal Binary Appendix E Further Reading User’s Reference Guide Further Reading E-3 User’s Reference Guide Pinouts for Auxiliary port modem cable Appendix F Technical Specifications and Safety InformationPower requirements DescriptionEnvironment Software and protocols International Agency approvalsRegulatory notices North AmericaDeclaration for Canadian users Important safety instructionsBattery Telecommunication installation cautionsAppendix G About Sdsl User’s Reference Guide Glossary User’s Reference Guide Glossary User’s Reference Guide Remapping See network number remapping User’s Reference Guide Glossary User’s Reference Guide Numerics IndexIndex-2 Index-3 Index-4 Index-5 Index-6 Limited Warranty and Limitation of Remedies User’s Reference Guide