OpenVPN client not connecting to OpenVPN Server with IPv6

universe4

Hello.

IPv4 connection works well for me, but I'd like to change to IPv6 and have been trying to so for a while, but no success.
So I want the public IP to be a IPv6 IP from the OpenVPN server.

If I try to connect with the changes done for IPv6, it won't work.

OpenVPN server version → OpenVPN 2.5.5 x86_64-pc-linux-gnu
The client on Windows is version 3.3.7 (2979).

The OpenVPN is running on an AWS Lightsail server, the IPv6 address/protocol has been enabled there.
Also, UDP 1194 has been added to the IPv6 firewall on AWS (the same as I had done for ipv4, which worked).

The client config:

client
#proto udp #default disabled
#remote 3.90.225.180 1194 #default disabled
proto udp6 #added myself
remote 2600:1f18:1b43:3500:926d:f1ad:b771:286d 1194 #added myself
explicit-exit-notify
dev tun
resolv-retry infinite
nobind
persist-key
persist-tun
remote-cert-tls server
verify-x509-name server_p3BWe6YJaLBrM6Ly name
auth SHA256
auth-nocache
cipher AES-256-GCM
tls-client
tls-version-min 1.2
tls-cipher TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256
ignore-unknown-option block-outside-dns
setenv opt block-outside-dns # Prevent Windows 10 DNS leak
verb 3
<ca>
...
...
...

The server config:

port 1194
#proto udp ## default
dev tun
user nobody
group nogroup
persist-key
persist-tun
keepalive 10 120
topology subnet
server 10.8.0.0 255.255.255.0
;ifconfig-pool-persist ipp.txt
push "dhcp-option DNS 1.0.0.1"
push "dhcp-option DNS 1.1.1.1"
push "redirect-gateway def1 bypass-dhcp"
dh none
ecdh-curve prime256v1
tls-crypt tls-crypt.key
crl-verify crl.pem
ca ca.crt
cert server_p3BWe6YJaLBrM6Ly.crt
key server_p3BWe6YJaLBrM6Ly.key
auth SHA256
cipher AES-256-GCM
ncp-ciphers AES-256-GCM
tls-server
tls-version-min 1.2
tls-cipher TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256
client-config-dir /etc/openvpn/ccd
status /var/log/openvpn/status.log
verb 3
duplicate-cn ##allow multiple connections
###############
###new ipv6 config below added myself
proto udp6
server-ipv6 2600:1f18:1b43:3500::/64
tun-ipv6
push tun-ipv6
ifconfig-ipv6 2600:1f18:1b43:3500::1 2600:1f18:1b43:3500::2
push "route-ipv6 2600:1f18:1b43:3500::/64"

What could be the reason, do I miss anything? Appreciate any help! :geek:

universe4

The problem was, OpenVPN Client was not up-to-date, and the previous version had a bug with IPv6 support.

I am able to connect on IPv6 now, however when browser on the internet, the IPv6 is NOT used:

This is what the client shows:

Your IP: 2600:1f18:1b43:3500::1000

Server IP: 2600:1f18:1b43:3500:926d:f1ad:b771:286d

Port: 1194
Protocol: UDPv6

It seems that when browsing it is using the openvpn IPv4 and for IPv6 it says "Not detected".

What could be wrong?