rc.inet1-generated IPv6 nameserver entries cause host to fail parsing /etc/resolv.conf

Environment

• Unraid OS: 7.2.3

• Network management: /usr/local/etc/rc.d/rc.inet1

• host utility: BIND 9.20.15 (/usr/bin/host)

• Resolver library: libresolv.so.2

Configuration

• IPv6 enabled

• Static IPv6 DNS configured in /boot/config/network.cfg

• Example configuration:

  DNS6_SERVER1="2001:db8:abcd:1:53::"
  

Observed behaviour

• rc.inet1 generates /etc/resolv.conf containing IPv6 nameserver entries with a stripped : at the end when the address is compressed.

• Certain IPv6 textual representations written to /etc/resolv.conf cause host correctly to fail with:

  host: parse of /etc/resolv.conf failed
  

Reproducible cases

1. boot/config/network.cfg containing:
   

   DNS6_SERVER1="2001:db8:abcd:1:53::"
   

2. results in a /etc/resolv.conf containing:

   nameserver 2001:db8:abcd:1:53:
   

   Result:

   host example.com
   → host: parse of /etc/resolv.conf failed
   

3. /etc/resolv.conf containing:

   nameserver 2001:db8:abcd:1:53::
   

   Result:

   host example.com
   → works