Do I need to set tcpip_socket = true to allow remote connections to a postgresql database?
All you should need is:

listen_addresses = '*'


and then to modify pg_hba.conf to permit connections from the desired source.

This is stated in the comments on the (very old) article you were reading.

Try using the main PostgreSQL documentation, or up to date tutorials, in future.

See:


Connection and authentication settings
Client authentication