This breaking change reported in NODE-753 implements a restriction that is inconsistent with the behavior of the Python driver and which we rely upon to manage services across domains in our environment. As noted in PYTHON-591, the client should not be required to supply hostnames that match the configuration of the replica set.

If it's desirable to perform verification that client and server configurations are compatible, perhaps the server configuration should allow us to supply aliases for the replicas so that the client would be allowed to specify a hostname that is specific to its network configuration.

At any rate, a discrepancy between the replica set configuration and the client's URI should be a warning, as it is in Python, rather than preventing the client from connecting. This is important because we do not want to see a situation where we are put in lock-step to update configurations in our various client/server network environment.