I have come across several posts that restrict users from certain external resources, but haven't quite found info on my particular situation. That being...
We have one Zimbra server with an internal IP and external IP with no firewall in place between email and internet. What I am looking to do is stop web access for any one that is not coming from an IP on our LAN or connecting to our LAN through a VPN. Internal users should be able to send internally as well as externally, but users sitting at home with no VPN will not have access to their email. Our current version of Zimbra is 5.0.4.
As this is something I've never considered before, can someone begin pointing me in the right direction? I would prefer not to implement other hardware to incorporate this change if not necessary.