While DETER can be deployed behind a NAT, it is currently geared towards a public installation. The default internal networks are:
If you try to deploy a DETER installation with RFC1918 external addresses, they must not conflict with these subnets. Setting up a private DETER install requires more effort and is not recommended if it can be avoided.
If you are setting up a standard public site, but don't have DNS, we can give you a subdomain of deterlab.net.