{"draft":"draft-ietf-ntp-port-randomization-08","doc_id":"RFC9109","title":"Network Time Protocol Version 4: Port Randomization","authors":["F. Gont","G. Gont","M. Lichvar"],"format":["HTML","TEXT","PDF","XML"],"page_count":"9","pub_status":"PROPOSED STANDARD","status":"PROPOSED STANDARD","source":"Network Time Protocols","abstract":"The Network Time Protocol (NTP) can operate in several modes.  Some\r\nof these modes are based on the receipt of unsolicited packets and\r\ntherefore require the use of a well-known port as the local port. \r\nHowever, in the case of NTP modes where the use of a well-known port\r\nis not required, employing such a well-known port unnecessarily\r\nfacilitates the ability of attackers to perform blind\/off-path\r\nattacks. This document formally updates RFC 5905, recommending the\r\nuse of transport-protocol ephemeral port randomization for those\r\nmodes where use of the NTP well-known port is not required.","pub_date":"August 2021","keywords":["security","transport protocols"],"obsoletes":[],"obsoleted_by":[],"updates":["RFC5905"],"updated_by":[],"see_also":[],"doi":"10.17487\/RFC9109","errata_url":null}