Attempts to add or remove a node from the addnode list, or try a connection once.
nodestringREQUIREDcommandstringREQUIREDcurl --user myuser --data-binary '{"jsonrpc":"1.0","id":"1","method":"addnode","params":["192.168.0.6:8333","onetry"]}' -H 'content-type:text/plain;' http://127.0.0.1:8332/null