Нашел в SIP debug такую запись
<--- Transmitting (no NAT) to 192.168.0.25:60038 --->
SIP/2.0 489 Bad Event
Via: SIP/2.0/UDP 5.165.111.173:60038;branch=z9hG4bK-d8754z-27375bab0be67c87-1---d8754z-;received=192.168.0.25
From: <sip:11@192.168.0.200;transport=UDP>;tag=19373234
To: <sip:11@192.168.0.200 ...

