FYI, the upcoming version of gpt4 does considerably worse emulating function calls / generating code-like strings, but gets better again if you switch to the function call API: https://twitter.com/reissbaker/status/1671361372092010497
(My guess is the same is true of gpt-3.5, although I haven't tested it.)
Are there any useful alternative models though? Most I've found weren't particularly good at following instructions or using tools in the way langchain provides them.
mDNS would be used for the internal network to discover hosts. The proxy server would terminate SSL using a LetsEncrypt certificate before forwarding traffic to one of the internal nodes (discovered via mDNS).