Microsoft Exchange Server Instant Messaging uses the RVP
protocol to communicate over a TCP/IP network connection. This article tells
you how to interpret the Instant Messaging methods and the Hypertext Transfer
Protocol (HTTP) response codes you see in the Microsoft Internet Information
Services (IIS) log or in a Network Monitor trace. Instant Messaging uses both
RVP methods (Subscribe, Unsubscribe, Subscriptions, and Notify) and Distributed
Authoring Version (DAV) methods (Propfind, Proppatch, and ACL).
The RVP Methods Used by Instant MessagingSUBSCRIBE
This is the method for logon and "subscription" to a resource.
The SUBSCRIBE method is the first method used in any Instant Messaging
communication. The SUBSCRIBE method tells the resource's home server to notify
the "watcher" of any property changes. By default, a "watcher" subscribes to a
resource for 14,400 seconds (4 hours). The Instant Messaging client
re-subscribes to each resource approximately 5 minutes before the 4-hour period
ends. This time-out is not a configurable option.UNSUBSCRIBE
This method cancels resource subscriptions enabled by the
subscribe method. When you quit the Instant Messaging client or log off the
Exchange Server Instant Messaging service, the Instant Messaging client sends
an unsubscribe message for each user on its contact list.SUBSCRIPTIONS
This method retrieves a list of other Instant Messaging users
currently watching your status. To use the SUBSCRIPTIONS method in the Instant
Messaging client, click Options
on the Tools
menu, and then click View
on the Privacy
This method informs a subscriber that the user's status has
changed. The NOTIFY method is also used to send messages.
The DAV Methods Used by Exchange Server Instant MessagingPROPFIND
This method obtains information about a subscribed resource, such
as the display name or the current presence state (Online, Offline, and so on)
of a contact.PROPPATCH
This method changes the object's status. The seven possible
object statuses are Online, Appear Offline, Busy, Be Right Back, Away from
Computer, On the Phone, and Out to Lunch (these are not configurable). When
your Instant Messaging client logs on, your Instant Messaging status is set to
Online. This status is valid for 1,200 seconds (20 minutes). Every 15 minutes,
your Instant Messaging client reissues another PROPATCH method to reset this
20-minute timeout. If the Instant Messaging client does not update its status
within 20 minutes, the Instant Messaging Home Server marks the user as Offline
and notifies all the subscribers to this resource that his/her status has
changed to Offline. This time-out is not a configurable option.ACL
This is the method used to allow or deny other Instant Messaging
contacts to view your Instant Messaging status.
Common HTTP Response Codes
The following list explains some common HTTP response codes you
may see when you troubleshoot Exchange Server Instant Messaging. You can view
these response codes by viewing the IIS Logs or by performing a Network Monitor
Trace. By default, the IIS Logs are located in the %windir%\system32\logfile
RFC 2068 defines the following five classes of response
- 1xx: Informational - Request received, continuing
- 2xx: Success - The action was successfully received,
understood, and accepted.
- 3xx: Redirection - Further action must be taken in order to
complete the request.
- 4xx: Client Error - The request contains bad syntax or
cannot be fulfilled.
- 5xx: Server Error - The server failed to fulfill an
apparently valid request.
Exchange Server Instant Messaging Error Codes202 Successful
: A request has been successfully carried out and there is one
method or call in the packet. It is a single-status request.302 Object Moved
: This code indicates that the server is not the requested user's
home server. The response includes the new URL for the correct home server. A
response of this type is typically received from an Instant Messaging Router.
401 Access Denied
: This code indicates that the user name and password combination
for the requested resource is not valid. This response code is often seen if
the client workstation is configured to use a proxy server. If the logon
authentication is using NTLM and it is sent to the Instant Messaging Virtual
Server through a proxy server, the logon attempt will fail.
For additional information, click the
following article number to view the article in the Microsoft Knowledge Base:
Troubleshooting authentication failures in Instant Messaging
: It is normal to see at least two Access Denied responses during
each SUBSCRIBE request. This is part of the NTLM authentication
For additional information regarding the authentication
process, see the following Web site: 404 Not Found
: This response code usually indicates that the e-mail address
that you entered on the Instant Messaging client does not match a valid Instant
Messaging User Address. When you log on to the Instant Messaging client, try
using the Instant Messaging User Address. To verify this address, follow these
- Open Active Directory Users and Computers.
- Right-click the appropriate user, and then click Properties on the secondary menu that appears.
- Click the Exchange Features tab.
- Select Instant Messaging to highlight it, and then click
the Properties button.
- Note the Instant Messaging User Address.
: You are not limited to using the Instant Messaging User Address
if you have created an RVP record in DNS. Please refer to the Exchange 2000
Help file for more information; see the topics "Instant Messaging" and "DNS
For additional information about configuring
Instant Messaging logging, click the article number below to view the article
in the Microsoft Knowledge Base:
XADM: How to Configure Instant Messaging Logging