RCS and DNS: The NAPTR Record, (Mon, Jul 6th)

This write-up analyzes how RCS uses DNS NAPTR and SRV records—showing decoded t-shark queries/responses for fp-us-verizon.rcs.telephony.goog, explaining the SIPS+D2T service selection and the NAPTR→SRV→A/AAAA lookup flow—and notes that NAPTR regexes are unused in this observed traffic while suggesting the records may interest researchers and penetration testers.