DOCSP-48699-directConnection-Docker-admonition (#398)

Author: jmd-mongo

source/connect.txt

@@ -258,6 +258,17 @@ To connect to a replica set, you can either:
 - Explicitly specify the replica set name and members in the connection
   string.
 
+.. important::
+
+   When a replica set runs in Docker, it might expose only one 
+   MongoDB endpoint. In this case, the replica set is not discoverable, and specifying 
+   ``directConnection=false`` can prevent your application from connecting to it.
+   
+   In a test or development environment, you can connect to the replica set by specifying
+   ``directConnection=true`` in your connection URI. In a production environment, we
+   recommend configuring the cluster to make each MongoDB instance accessible outside of
+   the Docker virtual network.
+   
 Option 1: DNS Seedlist Format
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