188.8.131.52.8 OUT_R1/A9 RTS PDU
An outbound proxy implementation MUST NOT accept the OUT_R1/A9 RTS PDU in any state other than opened. If it is received in any other state, the outbound proxy MUST treat this PDU as a protocol error as specified in section 184.108.40.206.14.
If this RTS PDU is received in opened state, an implementation of the outbound proxy implementation MUST execute these steps:
Close the connection to the client and to the server.
Transition the state to the finished state.