OPC Remote Connection failure for some servers|Classic OPC: DA, A&E, HDA, XML-DA, etc.|Forum|OPC Foundation

I’m new to OPC DA and am having trouble connecting to a vendor supplied server from a remote machine using the Matrikon OPC explorer.

The software creates 3 opc servers when started, and I am able to use the explorer to connect to all three on the local machine. If I use the explorer from a remote machine, I am able to view the servers (the names populate in the explorer), but I receive a time-out message when I attempt to connect. I have all my DCOM security removed on the servers for testing (ANONYMOUS LOGIN,  EVERYONE, and my user all have full access and remote launch privileges). In addition, I also installed Matrikon’s test server and I am able to connect to that server without any problems remotely.

I have used both wire-shark and sys-internals process explorer to investigate the problem. When I attempt to connect to the failing server, I see the following exchange

Client: DECRPC Bind request

Server: DCERPC Bind ack

Client: IOXIDResolver ServerAlive2 request

Server: IOXIDResolver ServerAlive2 response

Auth over NTLM is sent and verified

Client: ISystemActivator RemoteCreateInstance

At this point, I see no response, and the process starts over with another bind, and eventually times out.

Investigating the windows log, I see the following error “The server {Class-ID} did not register with DCOM within the required timeout,” where Class-ID is the ID of my server.

When I look at process explorer, I can see the remote DCOM looking at the registry for 64 bit keys, but when I connect locally, it checks the WOW6432Node directories instead. My understanding is that the difference here is that since OPC DA is a 32 bit application, the remote calls should check the WOW6432Node directory as well for keys. The client is 32 bits, but running on a 64 bit windows server, so I am thinking that something is not being translated correctly. Does anyone know what registry keys I need to fix in order to make this connection work? I am not receiving much help from the vendor as they are primarily an instrument company who has purchased the software from a 3rd party.