tcpdump -i lo -nv port 5060
tcpdump: listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes
10:04:42.151423 IP (tos 0x0, ttl 64, id 52648, offset 0, flags [DF], proto UDP (17), length 365)
127.0.0.1.48219 > 127.0.0.1.sip: SIP, length: 337
OPTIONS sip:localhost:5060 SIP/2.0
Via: SIP/2.0/UDP 127.0.0.1:48219;branch=z9hG4bKh1728758634;rport
Max-Forwards: 70
To:
From: monit ;tag=264065394
Call-ID: 58469665
CSeq: 63104 OPTIONS
Contact: