addnode "node" "command"

Attempts to add or remove a node from the addnode list.
Or try a connection to a node once.
Nodes added using addnode (or -connect) are protected from DoS disconnection and are not required to be
full nodes as other outbound peers are (though such peers will not be synced from).

1. node       (string, required) The node (see getpeerinfo for nodes)
2. command    (string, required) 'add' to add a node to the list, 'remove' to remove a node from the list, 'onetry' to try a connection to the node once

null    (json null)

> bitcoin-cli addnode "" "onetry"
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "addnode", "params": ["", "onetry"]}' -H 'content-type: text/plain;'