{"draft":"draft-ietf-dnsop-avoid-fragmentation-20","doc_id":"RFC9715","title":"IP Fragmentation Avoidance in DNS over UDP","authors":["K. Fujiwara","P. Vixie"],"format":["HTML","TEXT","PDF","XML"],"page_count":"13","pub_status":"INFORMATIONAL","status":"INFORMATIONAL","source":"Domain Name System Operations","abstract":"The widely deployed Extension Mechanisms for DNS (EDNS(0)) feature in\r\nthe DNS enables a DNS receiver to indicate its received UDP message\r\nsize capacity, which supports the sending of large UDP responses by a\r\nDNS server. Large DNS\/UDP messages are more likely to be fragmented,\r\nand IP fragmentation has exposed weaknesses in application protocols.\r\nIt is possible to avoid IP fragmentation in DNS by limiting the\r\nresponse size where possible and signaling the need to upgrade from\r\nUDP to TCP transport where necessary. This document describes\r\ntechniques to avoid IP fragmentation in DNS.","pub_date":"January 2025","keywords":["DNS","IP Fragmentation","attack"],"obsoletes":[],"obsoleted_by":[],"updates":[],"updated_by":[],"see_also":[],"doi":"10.17487\/RFC9715","errata_url":null}