Changing the IP setup currently requires a restart. It is now possible to change the configuration of all network interfaces programmatically using the System Configuration API, but it's not possible to put such changes into effect on the fly, so you actually have to shut down your application to put the changes into effect, something that might not be allowable.
So let's say e.g. that I have a controller with dual network interfaces and I want to reconfigure one of the network interfaces (turn on DHCP e.g.) - but I do NOT want to stop the RT application, because it controlls processes via other interfaces, and those processes must be kept alive. If it was a Windows PC, I could have done it. On an NI controller, which is ironically then typically used for more critical tasks, I cannot.
Current workaround through NI Linux RT and Sys Config API: https://decibel.ni.com/content/message/103853#103853