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VPN connection over ipv6 not working

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I am connecting to my asus RT AX86S over ipv6 via an openvpn connection from my ax55. I get the routers to connect but no internet connectivity on the client side after the vpn connection is established.

Every now and then it gives below IP conflict error; though after disconnect / connect that error disappears and I get a blue checkmark.
I changed the LAN ipv4 addres ranges of both routers to not match (one is 192.168.50.* and the other one 192.168.75.*)



RT-AX55 in the Netherlands as openvpn client behind cable ISP modem in bridge mode. RT-AX55 has public wan ipv6 address
RT-AX86s in Switzerland as openvpn server behind optic fibre ISP modem . ipv4 is cgnat (no own public address); own ipv6 public address. Modem has firewall turned off.

RT-AX86s server set up:




RT-AX55 client set up


The open vpn config file was generated by the RT AX86s ; I amended the IPV4 adress to the IPV6 address and changed proto to UPD6

# Config generated by Asuswrt-Merlin 388.1, requires OpenVPN 2.4.0 or newer.

dev tun
proto udp6
remote [2a04:*************:c9ff:feea:b5e8] 1194
resolv-retry infinite
ncp-ciphers AES-256-GCM:AES-128-GCM:AES-256-CBC:AES-128-CBC
keepalive 15 60
remote-cert-tls server
Last edited:
OpenVPN client does not support IPv6 in Asuswrt-Merlin.
Thank you for your fast reply. What clients would then be able to connect to it ? (Or would any alternate set up work with these two routers, knowing the server side only has a public ipv6).
Thank you for your fast reply. What clients would then be able to connect to it ?
You'd have to setup the client on a PC/VM within your network.

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