Raspberry Pi OVPN Server with IPv6 unreachable for IPv4 Client?

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Luc7
OpenVpn Newbie
Posts: 2
Joined: Thu Jan 23, 2020 7:59 am

Raspberry Pi OVPN Server with IPv6 unreachable for IPv4 Client?

Post by Luc7 » Thu Jan 23, 2020 9:05 am

Hello,
I am running an OpenVPN Server on my Raspberry Pi 4 and I am able to reach this Server with another Raspberry Pi 4. Both work with IPv6.
If I try to reach the server with my laptop (Windows 10) it doesn't work, most likely because the laptop does not get an IPv6-Address. The first raspberry is connected to a fritzbox. The second raspberry and the laptop are connected to a mobile hotspot of a phone. The hotspot is able to give away IPv6-Addresses but for whatever reason the laptop does get an IPv4 Address. My Question right now is, how can I manage to connect the laptop to the Server? My current client config of the laptop looks like this:

dev tun
client
proto udp6
remote IPv6-Address-of-Server 1194 udp6
resolv-retry infinite
nobind
persist-key
persist-tun
ca ca.crt
cert client1.crt
key client1.key
remote-cert-tls server
cipher AES-256-CBC
comp-lzo
verb 3
tls-auth ta.key 1
auth-nocache

I connected the Server-Raspi to a DDNS-Service. If I resolve this url on my Laptop I do get an IPv4-Address, but that is simply the IP-Address of the Server-Raspi. If I resolve the same url with my other Raspi I get an IPv6-Address, the one the Server-Raspi gets from the Fritzbox.
Do I need to change sth. with the server config?

port 1194
proto udp6
dev tun
ca ca.crt
cert server.crt
key server.key
dh dh2048.pem
server 10.8.0.0 255.255.255.0
server-ipv6 fd00::1:1/112
push "route-ipv6 fd00::/64"
push "route 192.168.178.0 255.255.255.0"
push "redirect-gateway def1 bypass-dhcp"
client-to-client
keepalive 10 120
tls-auth ta.key 0
cipher AES-256-CBC
comp-lzo
user nobody
group nobody
persist-key
persist-tun
status /var/log/openvpn/openvpn-status.log
log /var/log/openvpn.log
verb 3
explicit-exit-notify 1
push "redirect-gateway def1"
;push "redirect-gateway ipv6" #I tried turning either one of them on and both, nothing works
auth-nocache

greetings Luc

Luc7
OpenVpn Newbie
Posts: 2
Joined: Thu Jan 23, 2020 7:59 am

Re: Raspberry Pi OVPN Server with IPv6 unreachable for IPv4 Client?

Post by Luc7 » Thu Jan 23, 2020 10:29 am

The issue had nothing to do with the openvpn-services. I just needed to set the value of DisableComponents under
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP6\Parameters\
to 0 and now I am able to connect my laptop to my Server.

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