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Check the IP-Address, which will be used for the communication between the just:in linux server and the User Interface (just:control).
Install just:control on a macOS based system, which has access to the just:in linux appliance (via the network).
Establish the connection to the just:in linux appliances appliance with just:control.
IP-Address
Normally the just:in linux appliance has multiple network connections. One gets used for communication purposes, like such as interacting with just:control and another one will be used for the storage system connection. In order to be able to access the just:in linux server with just:control, the IP-Address of the communication interface port is required (normally em1 gets used for that).
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