The implementation is line based with a maximum line size of 1000 octets. The default IPC mechanism are Unix Domain Sockets.
On a connect request the server responds either with an okay or an error status. For authentication check the server may send an Inquiry Response prior to the first Okay, and it may also issue Status messages. The server must check that the client is allowed to connect, this is done by requesting the credentials for the peer and comparing them to those of the server. This avoids attacks based on wrong socket permissions.
It may choose to delay the first response in case of an error. The server never closes the connection - however the lower protocol may do so after some time of inactivity or when the connection is in an error state.
All textual messages are assumed to be in UTF-8 unless otherwise noted.