EDNS Version 1 (EDNS(1))
ISC
It is impracticable to deploy new EDNS options, with EDNS version 0, on a global scale due to inconsistent server behaviour in deployed servers when a EDNS option is present in the query. Most existing EDNS option deployment has been small scale between essentially consenting implementations. When EDNS options were added to every outgoing recursive query made it became clear that trial and error to discover the level of EDNS version 0 support was not practicable. This document request that EDNS version 1 be assigned so that consistent well defined behaviour can be seen when a EDNS option is present.