<--- SIP read from TCP:10.221.21.250:5065 --->
SIP/2.0 503 Service Unavailable(Signaling Resources Unavailable)
From: "Unknown" <sip:[email protected]>;tag=as4863a746
To: <sip:10.221.21.250>;tag=80daf1225ed0ea156a85b5c5d1200
Call-ID: [email protected]:5160
CSeq: 102 OPTIONS
Via: SIP/2.0/TCP 10.221.8.24:5160;branch=z9hG4bK4750fce3
Server: Avaya CM/R015x.02.1.016.4
Content-Length: 0

<------------->
--- (8 headers 0 lines) ---
Really destroying SIP dialog '[email protected]:5160' Method: OPTIONS
Sending to 10.221.21.250:5065 (no NAT)
Looking for s in from-sip-external (domain 10.221.8.24)

<--- Transmitting (no NAT) to 10.221.21.250:5065 --->
SIP/2.0 200 OK
Via: SIP/2.0/TCP 10.221.21.250:5065;branch=z9hG4bK80427b2c5ed0ea15aa85b5c5d1200;received=10.221.21.250
From: sip:10.221.21.250:5065;tag=80427b2c5ed0ea159a85b5c5d1200
To: sip:10.221.8.24:5160;tag=as5f44e928
Call-ID: 80427b2c5ed0ea159a85b5c5d1200
CSeq: 35886 OPTIONS
Server: FPBX-15.0.16.42(16.9.0)
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
Contact: <sip:10.221.8.24:5160;transport=tcp>
Accept: application/sdp
Content-Length: 0


<------------>
Scheduling destruction of SIP dialog '80427b2c5ed0ea159a85b5c5d1200' in 32000 ms (Method: OPTIONS)
ykt-pbx01*CLI>