Server Redirection Using Address Forwarding

Plant SCADA allows you to temporarily transfer the communications of a server to another computer to assist with hardware maintenance and system analysis.

By including an address forwarding section within a citect.ini file, you can override a server's project-configured address, redirecting network traffic to a different address and port.

For example, if you would like to test a new server before adding it to a project configuration, you could make the necessary address forwarding adjustments within the citect.ini file of a single client to direct it to the new hardware. The server could be tested within the context of a system without having to recompile the project.

You need to make the necessary adjustments within the citect.ini file for every computer that is likely to be impacted by address forwarding.

For example, if you have a computer configured to run two I/O servers, and you would like to temporarily redirect one of them, then both server machines and every connecting client need to have the necessary address forwarding adjustments made to their citect.ini files, so that the servers are aware of each other.

If your system is configured to support network redundancy, a server may have multiple network cards. If this is the case, you need to consider the following when configuring a server redirection:

• Make sure the IP address configured for forwarding is the one that is currently being used by the destination server.

• If a hostname is used for an address forwarding target, make sure it is mapped to the IP address that is currently being used by the destination server. This mapping can be defined locally (via a hosts file) or globally (via DNS services).

• Make sure static IP addresses are used, not dynamic addresses.

Address forwarding is implemented using the following syntax within a citect.ini file:

[AddressForwarding]
<ClusterName>.<ServerName>=<IPv4 ipaddress>:<port>

Or:

[AddressForwarding]
<ClusterName>.<ServerName>=<IPv6 ipaddress>:<port>

Address forwarding is only interpreted and used during startup of Plant SCADA Runtime. It is recommended (but not necessary) that the Setup Wizard is run before running up a project to confirm your changes.