> ufw firewall ... kept on a strict allowlist with only my internal servers > I switched the MongoDB cluster over to the new servers. It sounds like they had

> ufw firewall ... kept on a strict allowlist with only my internal servers > I switched the MongoDB cluster over to the new servers. It sounds like they had multiple Mongo nodes on separate machines, communicating over the internet. Presumably the application(s) are also on separate machines and would need to communicate with Mongo. I think `docker network` has options to create a network across Docker daemon hosts? But that has some tradeoffs, I'm sure.