So far I have found the following to work best on my boxes to remove IPv6 as much as possible resulting in better stability of Unbound no longer crashing or hanging unresponsive at random or when forced performing IPv6 nslookups:
Unbound Custom options to remove all local and external domain AAAA responses in replies given to clients:
server: do-ip4: yes do-ip6: no prefer-ip4: yes prefer-ip6: no private-address: 10.0.0.0/8 private-address: 172.16.0.0/12 private-address: 192.168.0.0/16 private-address: 169.254.0.0/16 private-address: ::ffff:0:0/96 private-address: fd00::/8 private-address: fe80::/10 private-address: ::/0 private-address: :: local-zone: localhost.home.arpa transparent local-data: "localhost.home.arpa A 127.0.0.1" local-zone: localhost transparent local-data: "localhost A 127.0.0.1" local-zone: ip6.arpa redirect local-data: "ip6.arpa A 0.0.0.0" local-zone: 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa redirect local-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa A 0.0.0.0" local-zone: "::/0" static dns64-ignore-aaaa: *.* do-not-query-address: :: do-not-query-address: ::1 do-not-query-address: ::/0Shellcmd's added to Shellcmd package to load at boot to unload any auto created/started inet6 interfaces, add or relabel for any other interface names that show when running command prompt/console command ifconfig
ifconfig lo0 inet6 ifdisabled ifconfig igb0 inet6 ifdisabled ifconfig igb1 inet6 ifdisabled ifconfig ix0 inet6 ifdisabled ifconfig lo0 inet6 fe80::1%lo0 delete ifconfig lo0 inet6 ::1 deleteThese last two are system files, these adjustments here aren't saved in config.xml files so if until there is a patch or tick box added, they would need re-applied each system upgrade but do maintain general reboots -
edit /etc/inc/system.incsearch for 'localhost' around line 331 and comment out - ::1 IPv6 section of lines with /* at beginning, a * for each next line and */ at the end:
edit /etc/hosts.allow comment out line adding a #:
#ALL : [::1] : allow