OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

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ahx-fos
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OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by ahx-fos » Sat Jun 25, 2016 10:25 pm

Hi -

My cellphone provider is T-Mobile US. TMO appears to use a sole IPv6 network, which mimics IPv4 to the local OS. Since the most recent iOS OVPN app update, I am experiencing connectivity issues.

If I attempt to connect to my OpenVPN server via a hostname, I connect using UDP6 and my connection is like treacle. It's unusuable.
However, if I change my .ovpn file to connect via my (dynamic) IP, the app connects via UDP4 and everything flows as expected.

WTF is going on? Why am I being forced to use IPv6 if a hostname is used? I appreciate why it does this from a network perspective (ie, TMO using ipv6) but surely I should have the choice as to whether I connect via IPv4 or IPv6?

Currently, OpenVPN is *BROKEN* for T-Mobile USA (LTE) users until they change their hostname to an IP to force an IPv4 connection.

ahx-fos
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by ahx-fos » Mon Jun 27, 2016 10:35 pm

How do I raise this with the OpenVPN connect developers please? This is a critical issue and needs fixing in their next release.

TinCanTech
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by TinCanTech » Mon Jun 27, 2016 10:52 pm

If you have an IPv4 IP address for your server then it sounds like you have setup your DDNS solution badly.

ahx-fos
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by ahx-fos » Mon Jun 27, 2016 11:15 pm

TinCanTech wrote:If you have an IPv4 IP address for your server then it sounds like you have setup your DDNS solution badly.
You have no idea what you are talking about.

int3nt
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by int3nt » Tue Jun 28, 2016 12:55 am

ahx-fos wrote:WTF is going on?
:? :lol:

ahx-fos
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by ahx-fos » Tue Jun 28, 2016 1:26 am

int3nt wrote:
ahx-fos wrote:WTF is going on?
:? :lol:
You, also, clearly have no idea of the problem.

ahx-fos
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by ahx-fos » Tue Jun 28, 2016 2:42 pm

Here's a further discussion of this issue with other users being affected: https://www.reddit.com/r/tmobile/commen ... 6_openvpn/

TinCanTech
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by TinCanTech » Tue Jun 28, 2016 8:50 pm

Maybe you should have lead with that ..

Or even better ..
done your own research and read the work done by OpenVPN Devs to address the problem:
(referenced in your own link and clearly not read by you)
http://community.openvpn.net/openvpn/ticket/614
ahx-fos wrote:You have no idea what you are talking about
And you are such an expert ? Bad start .. I'm done with this .. ciao

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disqualified
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by disqualified » Tue Jun 28, 2016 9:00 pm

ahx-fos wrote:WTF is going on?
ahx-fos wrote:You, also, clearly have no idea of the problem.
TinCanTech wrote:Bad start .. I'm done with this .. ciao
For future ref this may help:
http://catb.org/~esr/faqs/smart-questions.html

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debbie10t
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by debbie10t » Tue Jun 28, 2016 9:10 pm

To quote from the openvpn bug trac:
cron2 wrote:As there is not much we can do about Apple, but we at least have multiple documented workarounds for their VPN weirdness, I think I'll close this ticket now. (There is a new iOS version coming, so if someone want to test variants on this, please add to the ticket what works and what doesn't)
Please add relevant details to the trac ticket.

ahx-fos
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by ahx-fos » Tue Jun 28, 2016 11:19 pm

TinCanTech wrote:Maybe you should have lead with that ..

Or even better ..
done your own research and read the work done by OpenVPN Devs to address the problem:
(referenced in your own link and clearly not read by you)
http://community.openvpn.net/openvpn/ticket/614
ahx-fos wrote:You have no idea what you are talking about
And you are such an expert ? Bad start .. I'm done with this .. ciao
I'm fully aware of that 'fix'. It still has no relation to the issue at hand. There is NO IPv6 network running on the OVPN server in question. The bug report you cite is not relevant in this case.

TinCanTech
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by TinCanTech » Tue Jun 28, 2016 11:35 pm

ahx-fos wrote:I'm fully aware of that 'fix'.
TinCanTech wrote:Maybe you should have lead with that ..
ahx-fos wrote:There is NO IPv6 network running
ahx-fos wrote:I connect using UDP6 and my connection is like treacle
ahx-fos wrote:The bug report you cite is not relevant in this case.
I fail to see how blaming openvpn for your network fail is relevant .. caio

ahx-fos
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by ahx-fos » Wed Jun 29, 2016 1:36 pm

TinCanTech wrote:
ahx-fos wrote:I'm fully aware of that 'fix'.
TinCanTech wrote:Maybe you should have lead with that ..
ahx-fos wrote:There is NO IPv6 network running
ahx-fos wrote:I connect using UDP6 and my connection is like treacle
ahx-fos wrote:The bug report you cite is not relevant in this case.
I fail to see how blaming openvpn for your network fail is relevant .. caio
For _my_ network fail? Last time I checked I didn't run TMUS's network.

Regardless, my point is still valid. It's erroneous for OpenVPN Connect to automatically choose ipv6 connectivity despite the issues it still raises (as referenced in the bug cited previous). There should be an option to force the connection to ipv(4|6).

TinCanTech
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by TinCanTech » Wed Jan 10, 2018 4:04 pm

ahx-fos wrote:
Wed Jun 29, 2016 1:36 pm
There should be an option to force the connection to ipv(4|6).
There is.
The manual wrote: proto indicates the protocol to use when connecting with the remote, and may be "tcp" or "udp".

For forcing IPv4 or IPv6 connection suffix tcp or udp with 4/6 like udp4/udp6/tcp4/tcp6.
It is not very well documented but it is an option you can try.

oat_bondmen
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by oat_bondmen » Wed Jan 10, 2018 5:01 pm

Thanks for the input.

However, the fix for this is to force T-Mobile to use an ipv4 profile using a custom carrier configuration within Apple Configurator. Once a user does this, ip4 is used again, fixing the brokenness with OpenVPN and T-Mobile ip6.

TinCanTech
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Re: OVPN connects via UDPv6 if hostname is used, UDPv4 if IP used

Post by TinCanTech » Wed Jan 10, 2018 11:59 pm

oat_bondmen wrote:
Wed Jan 10, 2018 5:01 pm
the fix for this is to force T-Mobile to use an ipv4 profile using a custom carrier configuration within Apple Configurator
So nothing to do with openvpn .. good to know.

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