Thank you so much for such fast response! To clarify, yes, the server is running using mod_wsgi-express; the package installation into python was mod_wsgi-standalone so that I could avoid the Mac's Apache which was being cranky about needing a signed certificate.
I ran mod_wsgi-express start-server myappscript.wsgi —host A.B.C.D
When I then tried to access from the same machine using A.B.C.D:8000 in the browser, for the first time it gave me the request to allow httpd to accept connections through the firewall! So that was great.
The other machine’s browser still wouldn’t connect to A.B.C.D:8000, but the traceroute did ping. However I was able on other machine to go to System Settings->Privacy and Security-> Local Network, and for the first time Firefox (browser I’ve been using) appeared as an option to access to Local Network. And yay, now second machine can access the website!
I will still need to convince the router to do port forwarding so that the external DYNDNS can talk to the :8000 and serve it under a nice name to the world, but I’m successfully sharing to the local network, so that’s not a mod_wsgi problem.
I’m really a biologist who codes out of necessity, and am therefore extra grateful not only for the open source packages but also the kind support!
Best.
Leann