Can not connect OPC Server related with svchost port 5355

[xfeng5]

Hi all,

Today I spent one day on testing my program with new Image of my company, I found that the client machine(192.168.1.5) can not connect to server machine (192.168.1.10), then I found If I create a new rule in Windows firewall exception list(Program:%SystemRoot%\system32\svchost.exe, Type: UDP, local port: Any, remote port:5355) Inbound Rules in client machine, the client can connect server successfully If I enable it.

So I am wondering why OPC UA need multicast during creating connection between server and client.

Can anybody explain anything for me?

Thanks a lot

xfeng

[Support Team]

We cannot reproduce the issue at out test machines.
The OPC UA client application needs the multicast name resolution. When the client calles GetEndpoints, the server returns the EndpointDescriptions. In most cases the EndpointUrl contains the hostname instead of the IP-address. If name resolution is not possible, the client cannot connect.
Please try to connect using GettingStarted example. In Session > SimpleConnect you can check the box UseDnsNameAndPortFromDiscoveryUrl to replace the returned EndpointUrl by the discovery url used as argument for GetEndpoints.