#
U XX.XX.XX.XX:5060 -> YY.YY.YY.YY:5060
REGISTER sip:YY.YY.YY.YY SIP/2.0.
Via: SIP/2.0/UDP 192
#
U YY.YY.YY.YY:5060 -> XX.XX.XX.XX:5060
SIP/2.0 200 OK.
Via: SIP/2.0/UDP ZZ.ZZ.ZZ.ZZ;rport=5
#
U XX.XX.XX.XX:5060 -> YY.YY.YY.YY:5060
REGISTER sip:YY.YY.YY.YY SIP/2.0.
Via: SIP/2.0/UDP 192
#
U YY.YY.YY.YY:5060 -> XX.XX.XX.XX:5060
SIP/2.0 401 Unauthorized.
Via: SIP/2.0/UDP 192.168.50.
#
U XX.XX.XX.XX:5060 -> YY.YY.YY.YY:5060
REGISTER sip:YY.YY.YY.YY SIP/2.0.
Via: SIP/2.0/UDP 192
#
U YY.YY.YY.YY:5060 -> XX.XX.XX.XX:5060
SIP/2.0 200 OK.
Via: SIP/2.0/UDP ZZ.ZZ.ZZ.ZZ;rport=5
exit