Microsoft KB Archive/301529

= Supported connection scenarios for Remote Assistance =

Article ID: 301529

Article Last Modified on 1/25/2006

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APPLIES TO


 * Microsoft Windows XP Professional
 * Microsoft Windows XP Home Edition

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This article was previously published under Q301529





SUMMARY
This article describes the supported connection scenarios for Remote Assistance.



MORE INFORMATION
In Remote Assistance, a novice can connect to an expert by using the following methods:
 * Windows Messenger
 * Send Invitation as an E-mail
 * Save Invitation as a File

The tables in this section describe which connection scenarios work.

NOTE: Both the Save Invitation as a File method and the Send Invitation as an E-mail method use the same technology so they are listed in the same table.

Save Invitation as a File and Send Invitation as an E-mail Methods
For additional information about how to use Remote Assistance, click the article number below to view the article in the Microsoft Knowledge Base:

300546 Overview of Remote Assistance in Windows XP

Internet Connection Firewall (ICF)
Windows XP ICFis designed to allow novice or expert requests to work. Remote Assistance works if either the novice or the expert is behind ICF.

Other Firewalls
The Remote Assistance connection is dependant on how the firewall is configured. When Windows Messenger is used, both the novice and expert are making outbound connections on port 3389. Most firewalls are configured to allow all outbound traffic but to restrict incoming traffic. In this case, if either the novice or the client is behind a firewall, Remote Assistance works as expected. If both the novice and the expert are behind firewalls, the connection depends on the inbound configuration of the firewall. In these situations, it is recommended that you use Windows Messenger to establish the Remote Assistance session. When either the Save Invitation as a File or Send Invitation as an E-mail method is used, the expert makes an outbound connection to the novice. The novice must be able to receive an inbound connection on port 3389; this port is the listening port that Remote Assistance uses. Most firewalls are configured to block incoming connections to this port; therefore, you must configure the firewall to open this port when you use Remote Assistance. These connections usually fail in scenarios where the novice is behind a firewall. In these cases, if the firewall cannot be opened, it is recommended that you use the Windows Messenger method when you use Remote Assistance.

UPnP-Compliant NAT
Remote Assistance is designed to work with UPnP NAT devices. Presently, Windows XP is the only NAT device that is UPnP-compliant. This technology allows a Windows XP client behind the NAT to request that incoming traffic to port 3389 be mapped to the client that is requesting Remote Assistance. Remote Assistance works as expected when the novice is behind a UPnP NAT.

For more information about UPnP-Compliant NAT support in Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:

323713 Description of Universal Plug and Play Features in Windows XP

NAT
When either the Save Invitation as a File or the Send Invitation as an E-mail method is used, Remote Assistance works as expected if the expert is behind a NAT device. When Windows Messenger is used, Remote Assistance works if either the novice or the expert is behind a NAT, but not if the novice and the expert are both behind a NAT.

Proxy Server
In some cases, Remote Assistance works when the expert is behind a proxy server. The expert's computer may need to have Proxy Client software installed. Proxy Client software is provided by the manufacturer of the proxy server. Contact your network administrator for more information. Remote Assistance does not work if the novice is behind a proxy server.

Keywords: kbfirewall kbenv kbinfo KB301529

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