# ping -6 -c 2 nlnetlabs.nl
PING nlnetlabs.nl(dicht.nlnetlabs.nl (2a04:b900::1:0:0:10)) 56 data bytes
From 2620:xx:0:xx::3fc (2620:xx:0:xx::3fc) icmp_seq=1 Destination unreachable: Address unreachable
From 2620:xx:0:xx::3fc (2620:xx:0:xx::3fc) icmp_seq=2 Destination unreachable: Address unreachable
--- nlnetlabs.nl ping statistics ---
2 packets transmitted, 0 received, +2 errors, 100% packet loss, time 1001ms

server:
        tls-cert-bundle: "/etc/pki/tls/certs/ca-bundle.trust.crt"
forward-zone:
        name: "."
        forward-addr: 1.1.1.1@853
        forward-addr: 1.0.0.1@853
        forward-addr: 2606:4700:4700::1111@853
        forward-addr: 2606:4700:4700::1001@853
        forward-tls-upstream: yes

# unbound-host -C cloudflare.conf nlnetlabs.nl
[1652280699] libunbound[1465:0] error: SSL_handshake syscall: No route to host
[1652280699] libunbound[1465:0] error: SSL_handshake syscall: No route to host
nlnetlabs.nl has address 185.49.140.10
[1652280699] libunbound[1465:0] error: SSL_handshake syscall: No route to host
[1652280699] libunbound[1465:0] error: SSL_handshake syscall: No route to host
nlnetlabs.nl has IPv6 address 2a04:b900::1:0:0:10
nlnetlabs.nl mail is handled by 1 mx.soverin.net.

Version 1.15.0
Configure line: --build=x86_64-redhat-linux-gnu --host=x86_64-redhat-linux-gnu --program-prefix= --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64 --libexecdir=/usr/libexec --localstatedir=/var --sharedstatedir=/var/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-pythonmodule --with-pyunbound PYTHON=/usr/bin/python3 --enable-dnstap --with-libnghttp2 --with-libevent --with-pthreads --with-ssl --disable-rpath --disable-static --enable-relro-now --enable-pie --enable-subnet --enable-ipsecmod --with-conf-file=/etc/unbound/unbound.conf --with-pidfile=/run/unbound/unbound.pid --enable-sha2 --disable-gost --enable-ecdsa --with-rootkey-file=/var/lib/unbound/root.key --enable-linux-ip-local-port-range
Linked libs: libevent 2.1.12-stable (it uses epoll), OpenSSL 3.0.2 15 Mar 2022
Linked modules: dns64 python ipsecmod subnetcache respip validator iterator
BSD licensed, see LICENSE in source package for details.
Report bugs to unbound-bugs@nlnetlabs.nl or https://github.com/NLnetLabs/unbound/issues