On Sat, Aug 12, 2017 at 05:07:00PM +0200, Michael Kress wrote:
> it seems that OpenVPN in P2P mode (static keys) doesn't configure and
> start the tun interface when there are no configured IPv4 addresses:
> OpenVPN 2.4.3
> In "void do_ifconfig()" of tun.c line 881: if (tt->did_ifconfig_setup)
> The flag tt->did_ifconfig_ipv6_setup is not considered at all. Is there
> a reason to not start an IPv6 only tun device? Maybe this has simply
> been overseen?

IPv6-only is currently not supported (it works if you do not use any
ifconfig at all inside OpenVPN, but not with --ifconfig/ifconfig-ipv6).

The reason is fairly simple - there's lots of assumptions inside OpenVPN
about "IPv4 will be there" and nobody has checked everything to make
sure nothing will blow up (or the blowups are fixed) in case IPv4 is

No hard technical reason, just a matter of available time.

(The routing layer *nowadays* actually happily deals with "no IPv4 
routes" - initially, the scenario "IPv6 routes, no IPv4 routes" caused a 

USENET is *not* the non-clickable part of WWW!
Gert Doering - Munich, Germany                             g...@greenie.muc.de
fax: +49-89-35655025                        g...@net.informatik.tu-muenchen.de

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