title: Stop SIP SUBSCRIBEs from endpoint
body: <p>I am working with SIP protocol, and I have an issue with an endpoint (ZTE). The endpoint sends a lot of SUBSCRIBE method messages and I want to stop that because i don't whant to implement it.
  I already tried to respond with 403 (Method Forbibben) and 405 (Method Not Allowed), but the endpoint is still sending SUBSCRIBE.</p>
  
  <p>What is the propper way to stop an endpoint to send that method?</p>
  
  <p>Thanks!</p>