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Netopia R2020 manual Basic IP Packet Components, Basic Protocol Types, Example TCP/UDP Ports

Models: R2020

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Security 14-29

Host: A workstation on the Network.

Packet: Unit of communication on the Internet.

Packet Filter: Packet ﬁlters allow or deny packets based on source or destination IP addresses, TCP or UDP ports, or the TCP ACK bit.

Port: A number that deﬁnes a particular type of service.

Filter Rule: A ﬁlter set is comprised of individual ﬁlter rules.

Filter Set: A grouping of individual ﬁlter rules.

Basic IP Packet Components

All IP packets contain the same basic “header” information, as follows:

Source IP Address	163.176.132.18

Destination IP Address	163.176.4.27

Source Port	2541

Destination Port	80

Protocol	TCP

ACK Bit	Yes

DATA	User Data

This header information is what the packet ﬁlter uses to make ﬁltering decisions. It is important to note that a packet ﬁlter does not look into the IP datastream (the User Data from above) to make ﬁltering decisions.

Basic Protocol Types

TCP: Transmission Control Protocol. TCP provides reliable packet delivery and has a retransmission mechanism (so packets are not lost). RFC 793 is the speciﬁcation for TCP.

UDP: User Datagram Protocol. Unlike TCP, UDP does not guarantee reliable, sequenced packet delivery. If data does not reach its destination, UDP does not re transmit the data. RFC 768 is the speciﬁcation for UDP.

And there are many more ports deﬁned in the Assigned Addresses RFC.

Example TCP/UDP Ports

TCP Port	Service	UDP Port	Service

20/21	FTP	161	SNMP

23	Telnet	69	TFTP

25	SMTP	387	AURP

Image 233

Netopia R2020 manual Basic IP Packet Components, Basic Protocol Types, Example TCP/UDP Ports

Contents

Netopia¨ R2020 Dual Analog Router Part Number Contents Part II Advanced Configuration Contents Multiple Network Address Translation and IP Setup Aurp Snmp Contents Part III Appendixes Contents User’s Reference Guide Page Small Ofﬁce connection to the Internet Small Ofﬁce connection to the Internet Direct Connection to a Corporate Ofﬁce Telecommuter Conﬁgured to accept incoming dial-up connections Page Part I Getting Started User’s Reference Guide Overview Features and capabilitiesChapter Introduction How to use this guide What you need Chapter Making the Physical ConnectionsFind a location Ethernet Telco Identify the connectors and attach the cablesTelco Line ports Netopia R2020 Dual Analog Router Back Panel PortsMaking the Physical Connections Netopia R2020 LED front panel Netopia R2020 Dual Analog Router Status LightsBefore running SmartStart Chapter Setting up your Router with the SmartStart WizardInstalled and properly conﬁgured. See User’s Reference Guide SmartStart Wizard conﬁguration screens Setting up your Router with the SmartStart WizardEasy or Advanced options screen. You can choose either Easy optionSetting up your Router with the SmartStart Wizard User’s Reference Guide Setting up your Router with the SmartStart Wizard Advanced option Dynamic conﬁguration recommended Conﬁguration tab Static 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 User’s Reference Guide Readying computers on your local network Chapter Connecting Your Local Area NetworkUser’s Reference Guide 10Base-T Connecting to an Ethernet networkAdding an external modem Connecting to a LocalTalk network Wiring guidelines for PhoneNET cabling Chapter Console-based Management Snmp Simple Network Management Protocol. See Snmp on Connecting through a Telnet sessionConﬁguring Telnet software Connecting a local terminal console cable to your routerNavigating through the console screens How to access the Easy Setup console screens Chapter Easy SetupEasy Setup console screens Screen similar to the following appears Easy Setup proﬁle Beginning Easy SetupIP Easy Setup Ethernet IP Address 192.168.1.1 Ethernet Subnet Mask Easy Setup Security Part II Advanced Configuration User’s Reference Guide Chapter WAN and System Configuration WAN Creating a new Connection ProﬁleDatalink PPP/MP Options Data Compression IPX Profile Parameters Remote IPX Network Viewing or editing connection proﬁles Change Connection Profile Profile Name System Conﬁguration screens Deleting connection proﬁlesNavigating through the System Conﬁguration screens System Conﬁguration featuresMaximum Packet Size 1500 Channel Usage Dynamic Bandwidth AllocationFilter Sets Firewalls Network Protocols SetupConsole Conﬁguration IP Address ServingDate and Time Security Upgrade Feature SetSnmp Simple Network Management Protocol Logging Installing the Syslog clientPPP MP Internal Modem Conﬁguration screen appears Chapter Managing Data CallsSpecifying telephone connections Atdt Auxiliary serial port HD-15 female OFFCustomizing the default proﬁle Default Answer Proﬁle for Dial-in ConnectionsHow the Default Answer Proﬁle works PAP Call acceptance scenarios Scheduled connections Adding a scheduled connection Viewing scheduled connectionsADD Scheduled Connection Cancel Set Once-Only Schedule Set Weekly ScheduleModifying a scheduled connection Deleting a scheduled connection Connection MeteringWeb-based management pages System Information Activity for your Frame relay DLCIs Accounting for switched interfaces onlyConnection Status Connect/Disconnect Router Budget Configuration Connection Budgets Connection Budget Configuration Budget Statistics WAN Event History Event History pagesDevice Event History Console-based management screens Connection Budget Setup Name Use Connection Profile Connection Budget Statistics Date and time setting Chapter Virtual Private Networks Tr ans it In tern etw ork Summary About Pptp tunnels on About Atmp Tunnels onAbout Pptp tunnels Pptp ConfigurationConfiguration Add Connection Profile Chap Local WAN IP Address 0.0 Remote IP Address Encryption support VPN Default Answer Profile QuickView VPN QuickViewDial-Up Networking for VPN Installing Dial-Up NetworkingCreating a new Dial-Up Networking profile Configuring a Dial-Up Networking profile Virtual Private Networks Windows 98 VPN installation Installing the VPN ClientWindows 95 VPN installation Connecting using Dial-Up Networking About Atmp Tunnels Atmp ConfigurationDES Local WAN IP Address 0.0 Remote IP Address Pptp Example Allowing VPNs though a firewallSelect Display/Change Input Filter Change Output Filter EnabledYes ForwardYes Source IP Address Atmp Example Source Port ID Dest. Port Compare Change Output Filter EnabledYes ForwardYes Source IP Address Chapter Multiple Network Address Translation and IP Setup User’s Reference Guide Supported traffic FeaturesNAT conﬁguration Easy Setup ProfileIP setup 255.255.255.0 NAT rules ADD NAT MAP Add NAT Map mymap Modifying map lists Show/Change NAT Map List screen appears Change NAT Map screen appears Moving mapsAdding server lists ADD NAT Server Modifying server lists Show/Change NAT Server List screen appears Deleting a server IP profile parameters Binding Map Lists and Server Lists+--NAT Map List Name Configuration Default Answer Profile Default Answer ProfileDefault Answer Proﬁle screen appears Associations NAT AssociationsNAT Associations +NAT Map List Name-+ MultiNAT Configuration Example Previous Screen Enter your ISP-supplied values as shown belowChange NAT Public Range ADD NAT MAP Firmware upgrades and NAT IP subnets For example Static routes Viewing static routes Adding a static route Deleting a static route Rules of static route installationModifying a static route Main Menu System Configuration IP Address Serving Client Default Gateway Dhcp NetBIOS Options NetBios Type To release these addresses, select Lease Management Served IP Addresses screen appearsDhcp Relay Agent MacIP Kip Forwarding Options You have ﬁnished your IP Setup IPX Features Chapter IPX SetupIPX Deﬁnitions Internetwork Packet Exchange IPXIPX address Service Advertising Protocol SAPSocket Routing Information Protocol RIPIPX Spooﬁng NetBIOSIPX setup Default Gateway Address IPX in the answer proﬁle Menu Configuration Default Answer ProfileOff Main Menu Statistics & Logs IPX routing tablesUser’s Reference Guide AppleTalk protocol Chapter AppleTalk SetupAppleTalk networks AT Routing Table Routers and seeding MacIPInstalling AppleTalk Upgrade Feature Set Conﬁguring AppleTalk EtherTalk SetupLocalTalk Setup Aurp Free Trade Zone Aurp setupViewing Aurp partners Modifying an Aurp partner Adding an Aurp partnerConﬁguring Aurp Options Deleting an Aurp partnerReceiving Aurp connections AppleTalk Setup User’s Reference Guide Quick View status overview Chapter Monitoring ToolsGeneral Status Status lights Current StatusGeneral Statistics Statistics & LogsGeneral Statistics WAN Connection Statistics Event HistoriesWAN Event History Current Date Routing Tables IPX routing table IP routing tableAppleTalk routing table IPX Sap Bindery tableServed IP Addresses IP Address Lease Management screen appears Snmp Community strings Snmp Setup screenSnmp traps Viewing IP trap receivers Setting the IP trap receiversModifying IP trap receivers Deleting IP trap receiversUser’s Reference Guide Suggested security measures Chapter SecurityProtecting the conﬁguration screens User accountsProtecting the Security Options screen Dial-in Console Access Telnet access Enable SmartStart/Web ServerAbout ﬁlters and ﬁlter sets What’s a ﬁlter and what’s a ﬁlter set?Filter priority How ﬁlter sets workPacket First filter Match? Yes ﬁlter’s actions How individual ﬁlters workﬁltering rule Parts of a ﬁlter161 Aurp AppleTalk 387 Internet service TCP portWho 513 Port number comparisonsInternet Control Message Protocol Putting the parts togetherTransmission Control Protocol User Datagram ProtocolFiltering 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 destinationNetopia R-series Router ADD this Filter NOW Cancel Viewing ﬁlters Viewing ﬁlter setsModifying ﬁlters Deleting ﬁltersSample IP ﬁlter set Modifying ﬁlter setsDeleting a ﬁlter set TCP Icmp UDP Possible modiﬁcations User’s Reference Guide IPX ﬁlters Main Menu System Configuration Filter Sets FirewallsAdding a packet ﬁlter IPX packet ﬁltersViewing and modifying packet ﬁlters Deleting a packet ﬁlter IPX packet ﬁlter setsViewing and modifying packet ﬁlter sets Adding a packet ﬁlter setADD Filter SET NOW Cancel Viewing and modifying SAP ﬁlters IPX SAP ﬁltersDeleting a packet ﬁlter set Adding a SAP ﬁlter Deleting a SAP ﬁlter IPX SAP ﬁlter setsViewing and modifying SAP ﬁlter sets Adding a SAP ﬁlter setDeleting a SAP ﬁlter set Firewall tutorial General Firewall TermsExample TCP/UDP Ports Basic IP Packet ComponentsBasic Protocol Types Binary Representation Firewall design rulesFirewall Logic Established Connections Logical ANDingImplied Rules This is an example of the Netopia IP ﬁlter set screen Filter BasicsExample IP Filter Set Screen Example Example FiltersExample Network Example Example Using the SecurID token card Token Security AuthenticationKey Security Authentication Features of the Netopia R2020 Securing network environmentsConﬁguring for security authentication Security authentication componentsEstablishing a dial-on-demand DOD connection call Connecting using security authenticationCurrent Connection Status Establishing a manual connection call Chapter Utilities and Diagnostics Start Ping PingUtilities and Diagnostics Stop Ping TimeTrace Route Telnet client Secure Authentication MonitorTransferring conﬁguration and ﬁrmware ﬁles with Tftp Factory defaultsDisconnect Telnet Console Session Updating ﬁrmware Downloading 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 User’s Reference Guide Part III Appendixes User’s Reference Guide Conﬁguration problems Appendix a TroubleshootingNetwork problems SmartStart TroubleshootingConsole connection problems How to reach us Power outagesTechnical support Before contacting NetopiaOnline product information Netopia Bulletin Board Service 1Product information can be found in the following FAX-BackFinding an Internet service provider Appendix B Setting Up Internet ServicesUnique requirements Setting up a Netopia R2020 accountPricing and support ISP’s Point of presenceLocal LAN IP address information to obtain NAT-disabled Local LAN IP address information to obtain NAT enabledSmartIP Obtaining information from the ISPRemote WAN IP address information to obtain About IP addressing What is IP?Appendix C Understanding IP Addressing Subnets and subnet masks Subnet masks Example Using subnets on a Class C IP internetISP Network Network conﬁgurationBackground Example Working with a Class C subnetDistributing IP addresses 255.255.255.224 Technical note on subnet maskingDhcp Address Serving Netopia R2020 Dhcp Server CharacteristicsConﬁguration Manually distributing IP addresses Using address servingMacIP Serving Serve dynamic WAN clientsUnderstanding IP Addressing C-9 Tips and rules for distributing IP addressesDhcp example Internet Nested IP subnets0.0 C.1 WAN Packet header types BroadcastsUser’s Reference Guide 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 InformationDescription Power requirementsEnvironment VDC input AmpsRegulatory notices Software and protocolsAgency approvals Declaration for Canadian users Battery Important safety instructionsTelecommunication installation cautions User’s Reference Guide Outbound data 33.6K 67.2K Inbound data 56K 112K Appendix G About 56K Line AccessUser’s Reference Guide Bps See bits per second GlossaryUser’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