I get the error Cannot ioctl TUNSETIFF tun0: File descriptor in bad state (errno=77)

>>What was happening
>>earlier was that I built openvpn first, then realized I needed to build
>>the tun/tap kernel module, so built that and then rebuilt openvpn - but
>>configure (god bless it) used the cached result of NOT finding if_tun.h.
>> I cleared configure's cache and rebuilt it again - this time it found
>>"tun/tap v1.4". Now I'm onto a new set of problems though. Now I get:
>>34: Cannot ioctl TUNSETIFF tun: File descriptor in bad state (errno=77)
> Though I've never seen this error personally, it has been talked about
> extensively on the vtun list (another tunneling daemon that uses the TUN/TAP
> driver).
> Go to
> and search for "bad state".
> It appears to be caused by a mismatch between the tun/tap kernel module and
> the kernel itself.
> What kernel version are you using?
> Because in versions 2.4.6 and higher, the TUN/TAP module is integral to the
> kernel -- if you try to build an external version of the module, rather than
> using the one already bundled, it will likely fail.

Also I've read a few posts that suggest that /usr/src/linux needs to point
to headers that match the running kernel. Depending on what Sean has, it
may be worthwhile to ensure all the various versions
(kernel/headers/tunTap) all match.

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Last modified 9 years ago Last modified on 01/30/14 16:17:17