How can I get PHP8 with OCI8 to connect to a remote Oracle database using oci_connect from inside a Docker container?

Question

I have a vanilla PHP Docker container with Oracle Instant Client installed, and the oci8 extension installed and added to the php ini.

I have a pretty bland php script to test the oci_connect method:

$connection = oci_connect($dbCredentials['dbUser'], $dbCredentials['dbPass'], $connectString);

This works as expected from outside the container, but is throwing a timeout from within the container:

ORA-12170: TNS:Connect timeout occurred

I suspect there's something in the networking between the container and my local, any one have any suggestions?