First of all your hosts file is incorrect (possibly), earlier you mention that your LAN is 192.168.x.x and your hosts file has 192.0.0.180. Also in those results you seem to have no A or MX records for your zimdomain.zim domain. Correct those and your problem should go away.
Take a look at the
Split DNS article in the wiki, it describes how to set-up your local DNS server. See how you get on with that and post any questions or further problems.