Fixing the SSH forwarding error “administratively prohibited: open failed”

Attempting to forward a PostgreSQL port from a remote server to localhost, I saw the following error in the SSH client log:

debug1: All remote forwarding requests processed
debug1: Connection to port 5432 forwarding to localhost port 5432 requested.
debug1: channel 4: new [direct-tcpip]
channel 4: open failed: administratively prohibited: open failed

Turns out that the tunnel string 5432:localhost:5432 had an issue where the localhost portion did not resolve on the server side, switching to 5432: solved the issue, and forwarding proceeded as expected.