IPv6 traffic not tunneld through VPN client

[Senilicus]

Hi all,

I am running ASUS-WRT Merlin, version 386.7 on my ASUS-RT-AX86U. My internet provider supports full dual-stack IPv6 and I have
activated IPv6 on the router. Everything works fine. I have tested this at https://test-ipv6.com.

When I turn on my VPN client, (Mullvad), The IPv4 traffic is re-directed through the tunnel, but the IPv6 traffic runs outside the tunnel. Mullvad supports IPv6 and according to their support staff they have more reports of this problem. The easiest solution of course is just turning of IPv6.

Does anyone here has the same experience when using IPv6 and VPN, either with Mullvad or an other VPN provider?

TIA, Charles

 

[learning_curve]

@Senilicus Yes - in a word

Currently... the Open VPN Client (that's on the Asus router), does NOT re-direct the IPv6 traffic through the tunnel. It's covered in more detail in THIS previous thread and in the thread that's linked from within it.

There is an easy "workaround" but you've already seen it (Turn off IPv6 ) or, instead, you could (successfully) use a 3rd party VPN Client, on any device that's external from your router. That will re-direct both IPv4 and IPv6 traffic (for that specific device only) without any errors or leaks.

That's what I'm doing, in the interim until the Router's Open VPN Client is updated.

 

[Threska49]

@Senilicus Yes - in a word

Currently... the Open VPN Client (that's on the Asus router), does NOT re-direct the IPv6 traffic through the tunnel. It's covered in more detail in THIS previous thread and in the thread that's linked from within it.

There is an easy "workaround" but you've already seen it (Turn off IPv6 ) or, instead, you could (successfully) use a 3rd party VPN Client, on any device that's external from your router. That will re-direct both IPv4 and IPv6 traffic (for that specific device only) without any errors or leaks.

That's what I'm doing, in the interim until the Router's Open VPN Client is updated.

Does PPTP/L2TP/IPSec have this issue?

 

[Senilicus]

@Senilicus Yes - in a word

Currently... the Open VPN Client (that's on the Asus router), does NOT re-direct the IPv6 traffic through the tunnel. It's covered in more detail in THIS previous thread and in the thread that's linked from within it.

There is an easy "workaround" but you've already seen it (Turn off IPv6 ) or, instead, you could (successfully) use a 3rd party VPN Client, on any device that's external from your router. That will re-direct both IPv4 and IPv6 traffic (for that specific device only) without any errors or leaks.

That's what I'm doing, in the interim until the Router's Open VPN Client is updated.

@Senilicus Yes - in a word

Currently... the Open VPN Client (that's on the Asus router), does NOT re-direct the IPv6 traffic through the tunnel. It's covered in more detail in THIS previous thread and in the thread that's linked from within it.

There is an easy "workaround" but you've already seen it (Turn off IPv6 ) or, instead, you could (successfully) use a 3rd party VPN Client, on any device that's external from your router. That will re-direct both IPv4 and IPv6 traffic (for that specific device only) without any errors or leaks.

That's what I'm doing, in the interim until the Router's Open VPN Client is updated.

Thanks for your reply. I will disable IPv6 for now and maybe some day there will be a firmware update for the OpenVPN client on the router.

 

[learning_curve]

Does PPTP/L2TP/IPSec have this issue?

The OP's post (and my previous post) was about IPv6 tunnelling via the Open VPN Client that's on the Asus router, so that excludes any PPTP/L2TP/IPSec tests. My own LAN client devices, use either 3rd party Open VPN or WireGuard Clients, so again they exclude any PPTP/L2TP/IPSec tests.

Somebody else might have tried an PPTP/L2TP/IPSec Client on the router itself and/or on the LAN's client devices & verified IPv4 and IPv6 tunnelling, but you'd perhaps, need to start a new thread to enquire about that.

 

[qiuyan81]

Asus router can't use ipv6, including vpn, ddns, webiui, etc. I have tried it all, but it doesn't work

 

[learning_curve]

Asus router can't use ipv6, including vpn, ddns, webiui, etc. I have tried it all, but it doesn't work

To confirm:

IPv6 VPN - Clients? Yes. Servers? No, this was recently updated (RMerlin firmware) to function correctly.

IPv6 DDNS - Yes. Still isn't fully sorted yet by Asus on their routers, but... You could apply a workaround, by following the 1st section of this page but also including IPv6 within your own inadyn.conf file. This would mean that you are then using customised In-a-dyn commands and excluding the router's DDNS client processes.

IPv6 webui - Almost. Again it's a workaround, one which is dependent on fully functioning IPv6 DDNS ^^. I found out this for myself, after it came up in a discussion on about a previous Alpha build test. Here's the relevant post

 

[qiuyan81]

To confirm:

IPv6 VPN - Clients? Yes. Servers? No, this was recently updated (RMerlin firmware) to function correctly.

IPv6 DDNS - Yes. Still isn't fully sorted yet by Asus on their routers, but... You could apply a workaround, by following the 1st section of this page but also including IPv6 within your own inadyn.conf file. This would mean that you are then using customised In-a-dyn commands and excluding the router's DDNS client processes.

IPv6 webui - Almost. Again it's a workaround, one which is dependent on fully functioning IPv6 DDNS ^^. I found out this for myself, after it came up in a discussion on about a previous Alpha build test. Here's the relevant post

vpn server? Haven't tried this, how do I configure it to enable it?OpenVPN Server or PPTP VPN Server or IPSec Server?

 

[qiuyan81]

To confirm:

IPv6 VPN - Clients? Yes. Servers? No, this was recently updated (RMerlin firmware) to function correctly.

IPv6 DDNS - Yes. Still isn't fully sorted yet by Asus on their routers, but... You could apply a workaround, by following the 1st section of this page but also including IPv6 within your own inadyn.conf file. This would mean that you are then using customised In-a-dyn commands and excluding the router's DDNS client processes.

IPv6 webui - Almost. Again it's a workaround, one which is dependent on fully functioning IPv6 DDNS ^^. I found out this for myself, after it came up in a discussion on about a previous Alpha build test. Here's the relevant post

I just tried to open the IPSec VPN server on the router, but the ios client cannot resolve the ipv6 link through the domain name.

 

[learning_curve]

I just tried to open the IPSec VPN server on the router, but the ios client cannot resolve the ipv6 link through the domain name.

As stated, when replying to you in my previous post:
"IPv6 VPN - Clients? Yes. Servers? No, this was recently updated (RMerlin firmware) to function correctly."
You've now seen for yourself, that the router's OpenVPN Server works just fine with IPv6. It will send the correct IPv6 data to any OpenVPN Client that's correctly configured e.g. On a remote device that has it's own OpenVPN Client. However, this (currently) does not include the OpenVPN Client, that is included in the router's setup. That will follow in due course. I don't know when, as I'm not involved in any way with that & I have no short-cut access to RMerlin! You should start a new thread, with all of your associated questions.