Zimbra Firewall

[CyberLogic]

First off I'm running the 6.07 version of Zimbra Virtual Appliance on VMWare ESXi 4.1. All LAN workstations can access the Zimbra website without issue. The zimbra server is also on the LAN. We have a VPN tunnel to another office that does not block any port traffice between the two networks. People on the LAN on the other VPN cannot access the zimbra server website which resides at the other end of the tunnel. Additionally, I forwarded the ports on the router to the internet to the zimbra server so employees could access the zimbra mail website from the internet. This is also not happening... So I'm wondering if there is a firewall or other mechanism in the normal install of Zimbra that would stop the server from working with machines outside of the LAN.