This article describes the supported connection scenarios for Remote Assistance.

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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.

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Windows Messenger

	Windows XP Internet Connection Sharing (ICS)	Windows Millennium Edition (Me) ICS	Non-Universal Plug and Play (UPnP) Network Address Translation (NAT) Device	UPnP NAT Device
Novice	Yes	Yes	Yes	Yes
Expert	Yes	Yes	Yes	Yes
Novice and Expert	Yes	Yes	No	Yes

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Save Invitation as a File and Send Invitation as an E-mail Methods

	Windows XP ICS	Windows Me ICS	Non-UPnP NAT Device	UPnP NAT Device
Novice	Yes	Yes	No	Yes
Expert	Yes	Yes	Yes	Yes
Novice and Expert	Yes	Yes	No	Yes

For additional information about how to use Remote Assistance, click the article number below to view the article in the Microsoft Knowledge Base:

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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.

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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.

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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:

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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.

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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.

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