Netopia R2121 D-4 Users Reference Guide, Netopia Router

D-4 User’s Reference GuideAs you can see, when Workstation A and Workstation B transmit an IP packet to the WWW Server on the Internet, they have unique source IP addresses on the LAN interface but potentially the same source por ts, which in this case is 400. When the Netopia R2121 receives these packets, the source IP addresses are substituted with the single globally unique IP address that was acquired on the WAN interface which is 200.1.1.40. Now both IP packets have the exact same source IP address (200.1.1.40) and source ports (400). The way the Netopia R2121 is then able to distinguish between the two IP packets is to change the source TCP or UDP ports and keep this information in an internal table. As seen above, the source por t for Workstation A has been changed to 5001 and the source port for Workstation B has been changed to 5002.If you were to look at the internal port mapping table that is maintained by the Netopia R2121, it would look similar to the following:NetopiaRouter

Wkstn A to Netopia

Src IP: 192.168.5.2

Dst IP: 163.176.4.32

Src Port:: 400

Dst Port:: 80

Workstations

A & B

Netopia Router

LAN: 192.168.5.1

WAN: 200.1.1.40

Netopia to ISP Router

Src IP: 200.1.1.40

Dst IP: 163.176.4.32

Src Port:: 5001

Dst Port:: 80

ISP Router to WWW

Src IP: 200.1.1.40

Dst IP: 163.176.4.32

Src Port:: 5001

Dst Port:: 80

WWW to ISP Router

Src IP: 163.176.4.32

Dst IP: 200.1.1.40

Src Port:: 80

Dst Port:: 5001

ISP Router to Netopia

Src IP: 163.176.4.32

Dst IP: 200.1.1.40

Src Port:: 80

Dst Port:: 5001

Netopia to Wkstn A

Src IP: 163.176.4.32

Dst IP: 192.168.5.2

Src Port:: 80

Dst Port:: 400

ISP Router

200.1.1.1

WWW Server

163.176.4.32

Wkstn B to Netopia

Src IP: 192.168.5.3

Dst IP: 163.176.4.32

Src Port:: 400

Dst Port:: 80

Netopia to ISP Router

Src IP: 200.1.1.40

Dst IP: 163.176.4.32

Src Port:: 5002

Dst Port:: 80

ISP Router to WWW

Src IP: 200.1.1.40

Dst IP: 163.176.4.32

Src Port:: 5002

Dst Port:: 80

WWW to ISP Router

Src IP: 163.176.4.32

Dst IP: 200.1.1.40

Src Port:: 80

Dst Port:: 5002

ISP Router to Netopia

Src IP: 163.176.4.32

Dst IP: 200.1.1.40

Src Port:: 80

Dst Port:: 5002

Netopia to Wkstn B

Src IP: 163.176.4.32

Dst IP: 192.168.5.3

Src Port:: 80

Dst Port:: 400

Contents

Main Page B Part I: Getting Started CC ss ttss nntt eenn Part II: Advanced Configuration Page Page Page Page Part III: Appendixes Page Page Page Conguration options for your Netopia R2121 Dual Analog Router Page Page 3. Direct Connection to a Corporate Ofce (Telecommuter) 4. Congured to accept incoming dial-up connections 5. Congured for two onboard and one external modem on the Auxiliary port Page Page Page How to use this guide Page Identify the connectors and attach the cables 2 Telco 3 1 Ethernet Power Page Netopia R2121 Dual Analog Router Back Panel Ports Page Netopia R2121 Dual Analog Router Status Lights Page Page Page Page Setting up your Router with the SmartStart Wizard SmartStart Wizard conguration screens Easy option Page Page Page Advanced option Sharing the Connection Conguring TCP/IP on Windows 95, 98, or NT computers Page Page Page Conguring TCP/IP on Macintosh computers Page Page Page Page Navigating SmartView router_IP_Address router_IP_address General Machine Information page Connection Proles page Event History pages Page Standard HTML Web-based monitoring pages router_IP_Address router_IP_address Page Page Page Connecting to an Ethernet network 10Base-T Adding a third modem Connecting to a LocalTalk network Wiring guidelines for PhoneNET cabling do not Page Page Page Page Connecting through a Telnet session Conguring Telnet software Connecting a local terminal console cable to your router terminal Navigating through the console screens Page Page Beginning Easy Setup Easy Setup prole IP Easy Setup Page Easy Setup Security Page Creating a new Connection Prole Page Page Page Viewing or editing connection proles Deleting connection proles System Conguration screens Navigating through the System Conguration screens System Conguration features Page Network Protocols Setup Filter Sets (Firewalls) IP Address Serving Date and Time Console Conguration SNMP (Simple Network Management Protocol) Security Upgrade Feature Set Logging Installing the Syslog client WAN and System Conguration 8-15 The following screen shows a sample syslog dump of WAN events: Page Page 9-2 Users Reference Guide Specifying telephone connections The Internal Modem Conguration screen appears. Page Default Answer Prole for Dial-in Connections How the Default Answer Prole works Page Page only any Scheduled connections Page Page Page Page Cost control feature -- call accounting Page Viewing call accounting statistics Page Page Page Page Using Network Address Translation Page Associating port numbers to nodes Using multiple Connection Proles Network Address Translation guidelines IP setup Page Page Page IP subnets Page Static routes Page Page Page IP address serving Page DHCP NetBIOS Options Page 10-20 Users Reference Guide The Served IP Addresses screen appears. To release these addresses, select Lease Management. MacIP (Kip Forwarding) Options Page Page IPX address Socket Routing Information Protocol (RIP) Service Advertising Protocol (SAP) NetBIOS IPX Spoong IPX setup must IPX in the answer prole Page IPX routing tables Page Page Page MacIP AURP Routers and seeding Installing AppleTalk Page Conguring AppleTalk EtherTalk Setup LocalTalk Setup AURP setup Page Page must Page Page General Status Current Status Status lights Statistics & Logs General Statistics Event Histories Page Page Routing Tables Page Page Served IP Addresses Page System Information SNMP The SNMP Setup screen SNMP traps Page Page User accounts Dial-in Console Access Enable SmartStart/SmartView/Web Server Telnet access Whats a lter and whats a lter set? About lters and lter sets Caution! How lter sets work Page How individual lters work Page Page local any less Design guidelines Working with IP lters and lter sets Adding a lter set Page Page Page Viewing lter sets Modifying lter sets Deleting a lter set A sample IP lter set Page Page Page IPX lters IPX packet lters IPX packet lter sets Page IPX SAP lters Page IPX SAP lter sets Page Firewall tutorial General Firewall Terms Basic IP Packet Components Basic Protocol Types Firewall design rules Page Filter Basics Example Filters Page Page Token Security Authentication Securing network environments Using the SecurID token card Security authentication components Conguring for security authentication Connecting using security authentication Page Page Page Page Ping Page Trace Route Telnet client Secure Authentication Monitor Disconnect Telnet Console Session Factory defaults Transferring conguration and rmware les with TFTP Updating rmware Caution! Downloading conguration les Uploading conguration les Transferring conguration and rmware les with XMODEM Updating rmware Caution! Downloading conguration les Uploading conguration les Restarting the system Page Page Page Page SmartStart Troubleshooting Console connection problems Network problems Power outages Technical support How to reach us Page Page Page SmartIP Obtaining information from the ISP Local LAN IP address information to obtain (NAT enabled) Local LAN IP address information to obtain (NAT-disabled) Page Page Subnets and subnet masks Example: Using subnets on a Class C IP internet Router A: LAN Customer Site B Internet Router B: Netopia R2121 A: LAN Example: Working with a Class C subnet Distributing IP addresses Technical note on subnet masking Conguration Manually distributing IP addresses Using address serving Tips and rules for distributing IP addresses Page Nested IP subnets Internet Page Broadcasts Packet header types Page Page Page Netopia Router D-4 Users Reference Guide Netopia Router Exported services Important notes Conguration Page Summary Page E-2 Users Reference Guide Decimal Binary Decimal Binary Decimal Binary Decimal Binary Page Page Page Page Page Description Power requirements Environment Software and protocols Agency approvals Regulatory notices Page Important safety instructions Page Page Page GG rr yy bits per second Comite Consultatif International Telegraphique et Telephonique (CCITT Trunk Line CND. ANSI (American National Standards Institute) DCE DTE seed router, non-seeding, seeding soft seeding SDLC (Synchronous Data Link Control). Class A, B, and C networks TCP/IP AURP broadcast internet address host seed router, hard seeding, seeding network number remapping non-seeding, seed router, seed router non-seeding, seeding, hard seeding Page Page IIIInn eexx ddee nndd xx