@mgjosh Thank you for the reminder, I need to update this!
sudo: unable to resolve host RailCoreII: Name or service not knownThe error message I was getting was due to an error in the hosts file.
DWC name was correct but the hosts file in /etc/... was incorrect.
Edited the file and all is working again.
The entry in the host file was RailCore II, spaces not allowed in Linux, change to RailCoreII and all started working correctly.