Example tune for clarity (reverse_ip)

Use a last octet which will highlight the hex nature in the example.
> ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.127}
f.7.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2