How to allow to connect BOINC client.

If you have Linux server with BOINC client on it and you want to connect GUI to that client, you need to configure BOINC:
  1. on the server mashine, that hosts your BOINC client, open /etc/boinc-client/cc_config.xml and edit it.
  2. Add to the /etc/boinc-client/cc_config.xml something like 
    <cc_config>
    <options>
    <allow_remote_gui_rpc>1</allow_remote_gui_rpc> 
    </options>
    </cc_config>
    For example - my config:
    <!--
    This is a minimal configuration file cc_config.xml of the BOINC core client.
    For a complete list of all available options and logging flags and their
    meaning see: https://boinc.berkeley.edu/wiki/client_configuration
    -->
    <cc_config>
      <log_flags>
        <task>1</task>
        <file_xfer>1</file_xfer>
        <sched_ops>1</sched_ops>
      </log_flags>
    <options>
    <allow_remote_gui_rpc>1</allow_remote_gui_rpc>.
    </options>
    </cc_config>
    Restart boinc on your server:
    service boinc-client restart
    Next, you should configure your firewall (in my case - ufw) to open 31416 port:
    ufw allow 31416