If a server is located on an internal network, it is normally prevented from being available to outside access, and the network group in the company will do this. It also will not normally have an externally accessible DNS because there is no need internally to allocate one, so internal systems reference either the abstract ‘localhost’ or a specific URI that, if used externally, will not lead to that server. If you want to set up a system for internal use only then you must use an internal a domain name and NOT http://localhost so the machine hosting the system can be identified in the network.
If you want to set up a system for both internal and external use, you MUST provide a domain name that can be resolved externally (else nobody can find the server). You also have to put the server in your DMZ in order to provide an adequate level of protection for your internal systems. This way internal systems can see the DMZ, as can external, but external are not invited in to the internal network.
It is down to you to ‘harden’ the DMZ server to resist the usual hacking and attacks, and to ensure that they are adequately firewalled. The firewall will need to allow Viewer access on specific ports (the ports you specified when you installed the Locklizard administration system). Locklizard do not offer advice and guidance on these topics because we have no specific knowledge as to the specific requirements of each publisher, their operational preferences or the presence of other systems that they are also seeking to protect on the same server(s).