AirVPN and IPv6 (IPv4 DS-Lite)

[trininja 1]

Hi staff,

I'm behind a IPv6 connection with IPv4 over DS-Lite tunnel and I have real performance problems with VPN now. Loading a website is a real pain, downloading is very slow und uploading is only 1/4 of my internet connection. I tested every server with every possible port/protocol combination with the same result. On a pure IPv4 connection there is no problem, only on IPv6 with IPv4 DS-Lite tunnel. My provider will change to this in some weeks and I'm one of the beta testers for this type of connection, so I will not have the chance to change back to pure IPv4.

Any ideas or solutions? ^^

[Staff 9972]

Hi staff,

I'm behind a IPv6 connection with IPv4 over DS-Lite tunnel and I have real performance problems with VPN now. Loading a website is a real pain, downloading is very slow und uploading is only 1/4 of my internet connection. I tested every server with every possible port/protocol combination with the same result. On a pure IPv4 connection there is no problem, only on IPv6 with IPv4 DS-Lite tunnel. My provider will change to this in some weeks and I'm one of the beta testers for this type of connection, so I will not have the chance to change back to pure IPv4.

Any ideas or solutions? ^^

Hello!

We don't support IPv6 at the moment, so your IPv6 traffic will be "IPv6 over IPv4" when tunneled to our VPN servers. It should NOT cause such performance decrease, unfortunately your tests suggest the contrary. In our plans, full support to IPv6 is currently not planned in the next two months.

Please contact us through our "Contact us" form, or write directly to info@airvpn.org explaining your issue (or just a link to this thread) so that we'll consider to refund you while at the same time keeping your account active for testing purposes, if you're interested.

Finally, a couple of questions: do you detect such performance decrease when you use different devices (i.e. not the DS)? How does the DS connect to a VPN server?

Kind regards

[trininja 1]

I have no chance to get arround the DS-Lite (http://en.wikipedia.org/wiki/IPv6_transition_mechanisms#Dual-Stack_Lite_.28DS-Lite.29) so I can't test without it. VPN on my smartphone with my mobile provider over normal IPv4 works just fine.

I have filled out a testreport for my technical supporter during the IPv6 betatest, so there is a chance that this problem is caused by some malfunction DS-Lite implementions. I will stay in touch with him and try to get a clear solution or problem description.

If this problem is due to problems with the IPv6 implemention I will consider this as a test on our side and force my support engineer to give me detailed help. If this problem is more globally because of problems with OpenVPN and IPv6 and DS-Lite, I would like to take your offer to help you with tests to get arround such problems.

Kind regards

[trininja 1]

Ok, it seems an odd problem nobody can tell me what it is:

Connection Speed over VPN is only 1/4 via FTP what I normaly get over VPN

Websites are not loaded, downloads via Browser is impossible.

Ping: works fine, no problems.

Email: works fine, no problems.

Telnet: Just fine.

FTP: Like a charm, but slow.

Browsers tested so far: IE9, FF15, Chrome 21, Safari, Opera. I just reinstalled my computer and had just OpenVPN, Viscosity, AirVPN Client and the browsers up with the same problem.

My tech support will set me back to full DualStack, maybe this will help. But still interested in testing IPv6 with you.

EDIT: I was able to verify this behaviour on my MAC with MAC OS X Lion (NOT Mountain Lion), programs have problems to download anything, browsers are empty, just plain email, ping works, ftp seems to work with reduced speed too.

[Staff 9972]

Ok, it seems an odd problem nobody can tell me what it is:

Connection Speed over VPN is only 1/4 via FTP what I normaly get over VPN

Websites are not loaded, downloads via Browser is impossible.

Ping: works fine, no problems.

Email: works fine, no problems.

Telnet: Just fine.

FTP: Like a charm, but slow.

Browsers tested so far: IE9, FF15, Chrome 21, Safari, Opera. I just reinstalled my computer and had just OpenVPN, Viscosity, AirVPN Client and the browsers up with the same problem.

Hello!

Is DNS resolution ok on Windows and Mac?

Can you please send us the connection logs of your various devices (Air client logs for Windows, Viscosity logs for Mac OSX Lion)?

Kind regards

[trininja 1]

DNS resolution works like a charm, I tested several websites with nslookup and ping. FTP with website url instead of ip works fine, email with normal serverurls works fine. On Win & MAC.

Logfiles: https://www.dropbox.com/sh/lm5ippxsggn0qie/AucPfP558k/Logs

[Staff 9972]

DNS resolution works like a charm, I tested several websites with nslookup and ping. FTP with website url instead of ip works fine, email with normal serverurls works fine. On Win & MAC.

Logfiles: https://www.dropbox.com/sh/lm5ippxsggn0qie/AucPfP558k/Logs

Hello!

The Air client logs do not show any particular problem, except an odd triple PUSH just after the initial handshake. The Tunnelblick logs show just one "Replay-window backtrack occurred [1]", which is not worrying. It might be an apparently random DNS problem. Please try to force 10.4.0.1 DNS server to test whether the problem is solved (please see here, especially if you change connection port: https://airvpn.org/specs ).

Kind regards

[trininja 1]

No, the problem doesn't get solved with this. It gots more complicated in some way.

With normal settings it tries to load the websites and does it in some way very very very slow (Google and Heise needed around 5-10 Minutes to load, Flash files like speedtest do not load.) and FTP uploads dowrk, and downloads are really a pain via ftp.

I will be back on full DuallStack in some days, so I can test if the problem is solved. Its frustrating, because I know that in 2-4 weeks every customer will be set to DS-Lite and so I won't be able to use VPN until you will support full IPv6. Well, I hope you will start tests soon.

[trininja 1]

Ok, I am back on full DualStack, no DS-Lite tunnel anymore. And what should I say: No problems anymore.

And I have the main cause for this problem: It is a DNS problem, the DualStack-Lite tunneling of IPv4 packets in IPv6 packets works, but the DualStack-Lite tries to get DNS via IPv6 DNS server, not via IPv4, this causes this problems.

Back on full DualStack there are no problems, because I now have back a real IPv4 IP and real IPv4 connection and not a virtual IPv4 IP adress within a tunnel over real IPv6.