Transmitting (no NAT) to 192.168.1.248:5060:
SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 192.168.1.248;branch=z9hG4bK2cf8ad150c1ac236;received=192.168.1.248
From: "6012" <sip:6012@192.168.1.1>;tag=56ff97350b50a041
To: <sip:6012@192.168.1.1>;tag=as216fd38c
Call-ID: f79d21bf22ef6155@192.168.1.248
CSeq: 100 REGISTER
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY
Contact: <sip:6012@192.168.1.1>
WWW-Authenticate: Digest realm="192.168.1.1", nonce="1a550246"
Content-Length: 0