How do I set up Elastix to respond to our VOIP provider's SIP OPTIONS Request? The provider's switch sends out a request every 30s and I am supposed to be able to to reply to it to keep my connection alive. I am able to make outbound calls, no problem. Inbound calls can only be made within 30s of the last activity. After that my provider marks my trunk as inactive and won't be able to receive calls. Please consider me a total noob about this as I have never worked with anything like this before. Thanks in advance!