OPC-UA server in a remote access computer - server

I am trying to connect an OPC-UA server with an OPC-UA client. I am using a remote desktop connection. Is it the reason that I am not getting any server discovered by Matlab OPC UA or Aspen CIMIO even though they are running?

"Discovered" or just "connected"? Connecting to the remote OPC UA server is normal process so if you cannot connect I would check if there is connection can be made in the first place (firewall) and if certificate is used and what is policy.
Can you put the server on your local computer and check the connection then?

Related

OPC UA Connection to IP Address (when hostname couldn't be resolved)

I'm trying to connect to OPC UA Server which is located over local intranet, though the OPC Server is exposing the Computer Name as a hostname when trying to connect through the given IP address and eventually error out as hostname can't be resolved.
While on the other side, Prosys OPC UA Client can successfully connect to it. I'm currently using Eclipse Milo, but would like to understand how other clients connect to IP Address rather than the hostname while I couldn't?
Asked and answered here: Java OPC-UA Client Eclipse Milo endpoint URL changes to localhost
Instead of using the sample code in that post there is now a helper method in EndpointUtil.updateUrl that you can use.

Connection refused by PLC when connecting with Milo OPC Client

I tried to clean up the ReadExample mini project for client repository from Milo OPC, and for endpoint i put the PLC ip address.
But there was no port in the plc configuration that i could configure.
When i do not specify a port, it says i cannot open a port to it.
If i specify a port, it says connection refused by the machine.
Is it possible to connect the client to the plc? or was i just hoping?
Also, i did remove the server part from the example, as stated in some other questions here about this subject.
Does the PLC have an embedded OPC UA server? Have you tried the default port 4840 yet?

Can connect to some but not all localhost OPC Servers

I am trying to connect to a local OPC server. It is one of 7 OPC servers on the computer. I can connect to all the other servers except for this one.
As far as I can tell I have the server-specific DCOM settings wide open. Is there anything I could be overlooking as to why I cannot connect to this server?
Again this is a local server, not a remote computer.
By can't connect I mean I can see the OPC server in an OPC client, so opcenum is working - but I get a "OPCServer.WinCC. CoCreateInstanceEx: : 80070005 (Access Denied)" error.
I have a similar problem with Unitronic OPC Server on Windows 10. The OPC client is SCADA Reliance 4. The OPC Server runs as local on the same PC as Reliance. The problem is that the user requires to run Reliance with OPC server with limited privileges. Unitronic OPC server runs only with increased privileges because it is unable to operate with lower privileges. If an OPC client runs with a lower privilege than an OPC server, it is unable to establish a connection because of the restrictions. For these reasons, user must run the OPC client using the "Run As Administrator" option and the connection is successfully established in this case.

What kind of proxy server is this?

I want to use this as a proxy server to connect many different clients with servers. Here is what I'm looking to do:
The server software on a user's computer would connect to a proxy server that is running on a VPS. It would pass in some kind of Key or authentication info to identify itself and then would maintain a persistent TCP connection to the proxy server.
A client application running on a mobile device or other computer would connect to the proxy server and pass in some kind of Key or authentication info. The proxy server would match the connection between the client and server based on their authentication info, and then forward all data back and fourth between the connections.
The proxy server would need to be able to handle multiple clients and servers connecting to it at once and use the authentication info to pair them up. There could be multiple clients connecting to the same server at the same time too. The connection from the client and server would both be outbound so that they are not blocked by firewalls. I wrote the client and server software, so I can make them work with any specific proxy.
What is the name of this kind of proxy server? And can anyone recommend any?
Thanks!

How can i know if someone in the network connected to the SQL Express 2008 on my system

I have installed a SQL Express 2008 Server on my Desktop for some local work. This has mixed authentication. I have enabled TCP/IP connection so that one colleague can connect to this server. However, this exposes the server to everyone in the network. How do i keep track of which PC in the network connected to this server and when ? This would just help me audit the usage of the server.
Well you can get information about current users, sessions, and processes in an instance by using
sp_who;
MSDN Documentation