$ docker run -d -p 4445:4444 selenium/standalone-firefox:2.53.0

$ docker ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a89435c68373 selenium/standalone-firefox:2.53.0 "/opt/bin/entry_poin…" About an hour ago Up About an hour 0.0.0.0:4445->4444/tcp determined_sammet

remDr <- remoteDriver(port = 4445L)
remDr$open()

Error in checkError(res) :
  Undefined error in httr call. httr output: Failed to connect to localhost port 4445: Connection refused

remDr <- remoteDriver(remoteServerAddr = "yourIP", port = 4445L)