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Basic Network Permissioning

Basic Network Permissioning is a feature that controls which nodes can connect to a given node and also to which nodes the given node can dial out to. It is managed at the individual node level by providing the --permissioned command line flag when starting the node.

If the --permissioned flag is set, the node looks for a file named <data-dir>/permissioned-nodes.json . This file contains the whitelist of enodes that this node can connect to and accept connections from. Therefore, with permissioning enabled, only the nodes that are listed in the permissioned-nodes.json file become part of the network. If the --permissioned flag is specified but no nodes are added to the permissioned-nodes.json file then this node can neither connect to any node nor accept any incoming connections.

The permissioned-nodes.json file follows the below pattern, which is similar to the <data-dir>/static-nodes.json file that is used to specify the list of static nodes a given node always connects to:

 [ 
     "enode://[email protected]:port1",
     "enode://[email protected]:port2",
     "enode://[email protected]:port3", 
 ]

Sample file: (node id truncated for clarity)

 [ 
   "enode://[email protected]27.0.0.1:30300",
 ]

Warning

Every node has its own copy of the permissioned-nodes.json file. If different nodes have different lists of remote keys, then each node may have a different list of permissioned nodes which may have an adverse effect on the network.