Directory Authorities bind DirPort to IPv6
We should encourage directory authorities on IPv6 - gabelmoo, tor26, and longclaw - to bind their existing DirPort to IPv6 as well as IPv4.
maatuska does this already.
From #18348 (moved):
Currently most of the dir auths Dir ports are only listening on their ipv4 address, including the dir auths with ipv6 OR addresses. An easy (but not necessary correct) solution is Dir Auth Op configure their dirauths so they accept ipv6 connections on the dir port. A better solution is tor knows when a dir port is ipv4 or ipv6 and chooses the correct corresponding ip address.