i See this status when i ngrep a number that passes 30 minutes.
U 95.107.130.50:5060 -> 192.168.1.201:5060
SIP/2.0 481 Unknown Dialog.
Via: SIP/2.0/UDP 95.107.162.230:5060;received=95.107.162.230;branch=z9hG4bK7456382a;rport=1091.
From: "V8271010190004652610" <sip:3558189189@95.107.162.230>;tag=as4ddc1d9d.
To: <sip:00390396956879@95.107.130.50>;tag=SDtovm599-45826b5f-13c4-55dec5eb-adc68f43-33fe.
Call-ID:
53f7667b30d4ba8b447d0dbc5aa089b4@95.107.162.230:5060.
CSeq: 104 BYE.
What is Unknown Dialog status for ?