You can find a portdefinition on your arduino in this path:

/usr/lib/python2.7/ciao/connectors/restserver/restserver.json.conf

{
 "name" : "restserver",
 "description" : "REST server connector for the Ciao Core",
 "authors": ["Arduino Team <[email protected]>;"],
 "repository" : "https://github.com/arduino-org/Ciao",
 "version" : "0.0.2",
 "params" : {
            "port" : 80
             },
 "log" : {
         "level" : "info"
         }
}

The confusing part is that your Arduino has a server client connection on it self from the cpu/linino server to the mcu/arduino client.

https://www.arduino.cc/en/Reference/CiaoRestServer

You can find a port definition for your Arduino in this path:

/usr/lib/python2.7/ciao/connectors/restserver/restserver.json.conf

{
 "name" : "restserver",
 "description" : "REST server connector for the Ciao Core",
 "authors": ["Arduino Team <[email protected]>;"],
 "repository" : "https://github.com/arduino-org/Ciao",
 "version" : "0.0.2",
 "params" : {
            "port" : 80
             },
 "log" : {
         "level" : "info"
         }
}

The confusing part is that your Arduino has a server-client connection to itself from the CPU/Linino server to the MCU/Arduino client.

https://www.arduino.cc/en/Reference/CiaoRestServer