Defaults to IPv4, if not UDP6 chosen?

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haraldh

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Joined: Mon Aug 31, 2020 11:34 pm

Post by haraldh » Mon Aug 31, 2020 11:36 pm
It looks like contrary to Securepoint Viscosity defaults to using IPv4 when connecting to our VPN-server, unless I specifically choose UDP6.

Is it possible to configure Viscosity to prefer IPv6 when connecting to the VPN-server, without breaking the possibility of falling back to IPv4?

Eric

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Joined: Sun Jan 03, 2010 3:27 am

Post by Eric » Tue Sep 01, 2020 9:17 am
Hi haraldh,

Thanks for the feedback. We'll take a look into adding an option that would allow IPv6 to be preferred for a future release.

In the mean time, this can be achieved by adding your address twice with different protocols. Simply set you Protocol drop down to UPD6, then add your address a second time with the protocol set to UDP4, for example you might have the following in your address field:
Code: Select all
vpn.server.com, vpn.server.com:1194:udp4
Regards,
Eric
Eric Thorpe
Viscosity Developer

Web: http://www.sparklabs.com
Support: http://www.sparklabs.com/support
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haraldh

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Joined: Mon Aug 31, 2020 11:34 pm

Post by haraldh » Tue Sep 01, 2020 8:03 pm
Thanks, I also noted that Viscosity defaults to be installed with OpenVPN Version 2.3.

This leads to the connection failing when configured as UDP6 and after 5 minutes when a re-negotiation happens.

I tried with "redirect-gateway ipv6" on the server-side, but since the client (and many out there are) still on 2.3, this also fails due to an unknown directive.

haraldh

Posts: 4
Joined: Mon Aug 31, 2020 11:34 pm

Post by haraldh » Tue Sep 01, 2020 8:05 pm
Tue Sep 01, 2020 9:17 amEric wrote:
Thanks for the feedback. We'll take a look into adding an option that would allow IPv6 to be preferred for a future release.
I think it would be safe to assume that if one has both an IPv4 and an IPv6 address, that the protocol stack would prefer IPv6. This is how almost all programs I know of behave. This is the first time I've seen it the other way around, and we have had dual stack for ages, practically from when the RFC's where still being written on IPv6.

Eric

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Joined: Sun Jan 03, 2010 3:27 am

Post by Eric » Wed Sep 02, 2020 8:54 am
Hi haraldh,

I certainly do understand what you are saying, however OpenVPN defaults to IPv4 first. We did prefer the happy eyeballs approach for a long time, however this generated a lot of complaints and we switched back to preferring IPv4 where available to keep in line with vanilla OpenVPN.

This may change with OpenVPN 2.5, though this is still some way off.

Regards,
Eric
Eric Thorpe
Viscosity Developer

Web: http://www.sparklabs.com
Support: http://www.sparklabs.com/support
Twitter: http://twitter.com/sparklabs
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