FS#2608 - sysntpd cannot acquire time on IPv6 only network

[openwrt-bot]

0x00:

I've encountered an issue with ntpd in OpenWrt where it cannot acquire the time on an IPv6 only network, it seems that the issue lies in dns resolution by ntpd as specifying an IPv6 address instead of a domain works as expected.

By the way, I believe only 2.pool.ntp.org returns IPv6 addresses in case anyone tries to reproduce my issue.

Possibly relevant: https://dev.archive.openwrt.org/attachment/ticket/12167/0001-busybox-make-ntpd-prefer-IPv6-addresses.patch

[openwrt-bot]

SimonIremonger:

I can confirm this issue does exist, in Master 2020-12-28 ...

When configured with IPv6-only networking (at least, no IPv4-default-route), there seems to be no attempts to ipv6 timesync, even though 2.openwrt.pool.ntp.org has AAAA-records!.

Installing 'ntpd' package seems to 'fix' this issue, i.e. would appear that the openwrt busybox ntp client build is where the problem lies...