The way to start the dirmngr in the foreground (as done by tools if no dirmngr is running in the background) is to use:
dirmngr --server -v
If a dirmngr is supposed to be used as a system wide daemon, it should be started like:
This will force it to go into the backround, read the default certificates (including the trusted root certificates) and listen on a socket for client requests. It does also print information about the socket used but they are only for compatibilty reasons with old GnuPG versions and may be ignored.