Hi All,

I have upgraded my downstream server to Windows Server 2012 R2. After upgrade my WSUS server is not synchronization with my upstream WSUS server. I am getting the below error while running the synchronization.

IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
at System.Net.ConnectStream.Read(Byte[] buffer, Int32 offset, Int32 size)
   at Microsoft.UpdateServices.ServerSync.ServerSyncCompressionProxy.GetWebResponse(WebRequest webRequest)
   at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
   at Microsoft.UpdateServices.ServerSyncWebServices.ServerSync.ServerSyncProxy.GetRevisionIdList(Cookie cookie, ServerSyncFilter filter)
   at Microsoft.UpdateServices.ServerSync.CatalogSyncAgentCore.WebserviceGetRevisionIdList(ServerSyncFilter filter, Boolean isConfigData)
   at Microsoft.UpdateServices.ServerSync.CatalogSyncAgentCore.ExecuteSyncProtocol(Boolean allowRedirect)

Hi Nirmal,

What operating system is the upstream server running? What steps did you take to upgrade the downstream? 

Up stream server is running on windows server 2012.

For upgrading downstream server i have built a new windows 2012 R2 server on it installed the WSUS services. 

• How did you do the upgrade, was it in-place, or a new machine? And did you migrate the WSUS role or just deploy a new instance?
• Are there any firewalls in place?
• Do you have other downstream servers connecting to the upstream, if so are those connecting ok?
• Do you have any clients connecting to the upstream?
• What are the build numbers on both servers?
• Are there any errors in the IIS log?

Please find the response below-

1-its a new machine.

2- Firewall is between upstream and downstream Server.

3- Just check other downstream servers having the same issue.

4- Clients connected to upstream server, patches are getting deployed on them.

5- Both server having Windows Server 2012 R2.

6- Not able to find any error in IIS logs.

Ok, if there is a firewall in place, can you connect to 8530 (or 8531 depending on what's configured) from the downstream to the upstream? (telnet upstream 8530) for example? 

If local clients can connect but remote downstreams can't that firewall would be a good starting place. When did the other downstreams stop syncing?