IO Server Processes Failing with Dual NIC

Is there any connection between the SCADA and Corp networks? Citect doesn't like to send a message on one network and receive a response from the other.

Are those two NICs in different subnets?

Dual NICs are normally used for network load balancing or redundancy. Have a look at Automatic Metric in your NICs' Advanced TCP/IP settings in Windows. In general, for load balancing applications, Automatic Metric should be selected (and Windows will do it automatically) while for redundancy, you should manually set the priority of NICs where a lower number stands for a higher priority). Normally, dual NICs should be in the same subnet for load balancing.

It appears that your application is for network redundancy. So you need to manually set up SCADA NIC in a higher priority in Windows. Questions for you

• Are machine names are used in Network Addresses in your SCADA project?
• If not, are IP addresses Static
• Are you using Encrypted Mode at runtime?

Yes, there are

There is a CORP IP address for the WebClient defined in networks the rest are all SCADA.
The corp is used for the CitectConnector
Citect has no need to send anything on the corp network

Not quite, the dual NIC is just for the Citect connector to talk to the historian seating in the corp network

• IP Addresses Used
• IP Address are static
• Mixed Mode

Are you set up like this?  192.168.215.xxx is the SCADA network. 192.168.15.xxx is the corporate network.

Yes, but SCADA is 192.XXX.XXX.XXX and CORP is 10.XXX.XXX.XXX

How did you define the default gateway? That should only be defined on one network card.

In that case, the problem seems to be in the connector configuration. It is expected that the Citect Connector for SCADA connection should be configured with 192.XXX.XXX.XXX while 10.XXX.XXX.XXX is used for Historian connection. How did you configure the connector?