Using ODBC Data Source Administrator (32-bit), I have set up a User Data Source configured with the PostgreSQL ANSI driver. Then, I use that DSN to create a Linked Server in SSMS.
I want to link another server in SSMS, also using a PostgreSQL ANSI driver, but when I go through the steps to Add the second DSN, I am returned to the configuration page for the existing DSN using that driver.
Naturally, each linked server has a unique IP address, so how do I Add a second Data Source instance in ODBC Data Source Administrator, using the same driver as the first instance?
After reading up on Microsoft's Documents pages, the missing piece became clear. I needed to name each instance uniquely. Inside the DSN driver setup/configuration window, I populated the "Data Source" field with a distinct name, even while each instance used the same PostgreSQL ANSI driver.
The following link is where I started. Even though it doesn't explicitly go into detail for this particular use case, it planted the seed of this idea.
https://learn.microsoft.com/en-us/sql/odbc/admin/managing-data-sources?view=sql-server-ver15