Having successfully started the database using the following command:

$ /opt/sqlanywhere17/bin64s/dbsrv17 -ga -x tcpip(port=49153) -n ftnode_sa /home/sa/sqlany17/ftnode_sa.db
SQL Anywhere Network Server Version 17.0.4.2053

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Database "ftnode_sa" (ftnode_sa.db) started at Thu Jul 13 2017 23:49
Database server started at Thu Jul 13 2017 23:49
Trying to start SharedMemory link ...
    SharedMemory link started successfully
Trying to start TCPIP link ...
Starting on port 49153
    TCPIP link started successfully
Now accepting requests
Press 'q' to shut down the database server

The database suddenly shuts down whenever I close SQL Central on a client machine.

Finished checkpoint of "ftnode_sa" (ftnode_sa.db) at Thu Jul 13 2017 23:58
Database "ftnode_sa" (ftnode_sa.db) stopped at Thu Jul 13 2017 23:58
Database server shutdown automatically after last database stopped
TCPIP listener on IP address (::):49153 is exiting
TCPIP listener on IP address 0.0.0.0:49153 is exiting
Database server stopped at Thu Jul 13 2017 23:58

Is there anyway I can prevent this from happening. I prefer to explicitly stop the database using dbstop, something like this:

/opt/sqlanywhere17/bin64s/dbstop -c "Server=ftnode_sa;uid=sadb;pwd=sadb;"

Clients should be able to connect and disconnect as and when. I could hack it and open a dummy client, but prefer not to create such spurious connections.