Polycom ViaVideo manual What’s a Network Address Translator?

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Appendix

Network Connection

What’s a Network Address Translator?

A NAT is a set of services on the router that allow you to operate a local network of devices, each with its own locally unique IP address, while communicating to the Internet through a router which presents a single, globally unique IP address to the outside world. Most small business and home office (SOHO) routers provide NAT services.

The NAT ensures that outgoing packets have a globally valid IP address, and that incoming packets go to the right device by translating between the internal IP address and the external IP address, owned by the router. This also adds an extra level of security by effectively masking the internal network behind a single external IP address.

A simplified explanation of how this translation takes place is that when an internal device sends an outgoing packet to the router, the NAT service either notes the internal IP address or the port number of the device, and attaches an identifier to the external IP address of the outgoing packet, substituting the router’s globally unique IP address for the device’s internal IP address. When the answering packet comes back, the NAT notes the indentifier, re-assigns the packet to the device’s internal IP address, and sends it on its merry way.

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ViaVideo User’s Guide

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Contents ViaVideo User’s Guide Page Patent Information WarrantyOther Restrictions Trademark InformationRADVision Statement Important SafeguardsRegulatory Notices FCC Notice Underwriters’ Laboratories’ StatementContents Network Connection System Information and DiagnosticsAudio Connection Troubleshooting Contents ViaVideo User’s Guide Viii Hardware Requirements System Requirements and InstallationSoftware Requirements Installing SoftwareInstalling Hardware Turn on the Camera Starting ViaVideoViaVideo built-in microphone Initial SetupHeadset with microphone Camera Calibration Using Manual DialingPlacing a Call Info icon Call status light IP address Chapter Using the Address Book or Speed Dialing New entry Edit entry Delete entry On-Screen Remote Control Answering Calls Ending a CallClosing ViaVideo Chapter Calling Features Using ViaVideoHang Up Using the Remote ControlAudio Mute VolumeSnapshot Minimize Window Information Screen AccessWindow Controls Picture in Picture PIPSending Snapshots Re-Size the ViaVideo DisplayLeaving a Callback Message Address Book and Speed Dial Using the Address BookDo This Local Entries Local and Global Address Book EntriesGlobal ILS Server Entries Display Global Address Go to the Directory Services screenRegister This System When Powered On Lock Using Speed DialDelete All Dial Controlling Audio and VideoControlling Audio Via the On-Screen RemoteVia the Audio Screen Mute Auto Answer Calls in the Audio screen System Muting VideoChapter Multiple IP Addresses Collaboration and Application SharingChapter Using the System Information Screens System Information and DiagnosticsSystem Information and Diagnostics Diagnostics Network Statistics Video Jitter Advanced StatisticsAudio Jitter Call Status Reset System Camera Calibration Generate Tone Setup Auto Answer Auto Start ViaVideo When Auto Start ViaVideo is selectedGeneral 323Mail Show Half-Size Display When Show Half-Size Display isShow Animations User NameDirectory Services Display Global Addresses Register this system when starting ViaVideoLAN and Internet IP Address Wins ResolutionDefault Gateway Host NameAudio Line Volume ControlMaster Volume Wave VolumeViaVideo Software SoftwarePC Software Dialing Speeds SetupGatekeeper Display IP Dialing Extension 323Multiple IP Addresses Gatekeeper Dialing Speeds Use Fixed Ports Quality of Service and FirewallsDynamic Bandwidth Auto discover NAT IP addressNAT outside WAN address IP PrecedenceChapter PC with Speakers Audio ConnectionPC with Headphones Headphones Only Headset with Attached Microphone Simple Connection Just a Modem, Thanks Pick Your Connection TypeRouter With Firewall Router With Firewall, Using a DMZRouter With NAT, No Firewall Through a Virtual Private Network Configure Your ConnectionSelect the System is Behind a NAT option Configure your ViaVideo for NATWhen you select Auto discover NAT IP Address, ViaVideo System Information screen Open and Assign Ports in the FirewallRouter With Firewall, Using a DMZ Assign your ViaVideo to the DMZ Through a Virtual Private Network Appendix What’s a Firewall? Is it Safe? Opening PortsPort Number Assignation What’s a DMZ? What’s a Network Address Translator? Appendix Problem Explanation Solution General TroubleshootingInfoDiagnosticsGenerate Audio TroubleshootingWave, and Master Volume ControlsWindows Control Panel Video TroubleshootingBandwidth option InfoSetupH.323QOSError Message Explanation Solution Error MessagesInstallation Errors ErrorsSetupH.323 Gatekeeper settingAppendix C