When setting up Virtualmin, we get the following error:
Default IP address is set to 10..., but the detected external address is actually 85. .. This is typically the result of being behind a NAT firewall.
We are behind an NAT firewall, using PORT forwarding, and the external IP address on the firewall is 85...*
If we switch the configuration to: Default IP address for DNS records: Automatically detect external address then the IP address is set to the external address and Virtualmin no longer complains of the error.
However, we have a number of internal services which need to access the server by website name.
For example, we have a sitemap creator which auto-creates the sitemap.xml based on the domain name. When attempting to query the Virtualmin DNS server, it gets the external IP address, not the internal one.
These connections then fail as the DNS address is the firewall external connection and not the Virtualmin server address.
What is the best way to resolve this?