Hopefully you won't have to do this. I did because the domain of the private network .local which is also the domain name of the public network (e.g. hercules.jp.local). You will have DNS trouble if you have this situation. You can either change the domain of the public or private network. Private network is easier. Here is how, on the frontend (we change from .local → .priv):

1. First find the name of your private network with rocks list network. (By default the private network is called private).
2. Set the rocks private domain name as follows: rocks set network zone private zone=priv
3. Then set the attribute used to store the private domain name rocks set attr Kickstart_PrivateDNSDomain priv
4. Note: the above may give you some error messages like Error: unknown host something.local. This is just because the hostname requires a reboot - LATER - for the change to take effect.
5. rocks sync config
6. rocks sync dns
7. rocks sync host network
8. Reboot the frontend

Unfortunately, this doesn't work 100%. In the /etc directory some files still refer to something.local instead of something.priv, Do a grep in /etc/ for .local and edit the files manually with vim.