On Tue, Jun 22, 2010 at 08:05:31PM -0700, Matt S wrote:
> I apologize in advance if this subject has been addressed but I was unable
> to turn up anything from a Google search and the manual pages did not quite
> yield enough information. IPv6 needs aside, what is the primary difference
> between tun(4) and gif(4)? When is it preferrable to use gif(4) over
> tun(4)? Is there any reason why I could not, say, perform IPSEC encryption
> over a tun(4) tunnel?
>
Huh? From the man pages:
The tun driver provides a network interface pseudo-device. Packets sent
to this interface can be read by a userland process and processed as
desired. Packets written by the userland process are injected back into
the kernel networking subsystem.
The gif interface is a generic tunnelling pseudo-device for IPv4 and
IPv6. It can tunnel IPv[46] over IPv[46] with behavior mainly based on
RFC 1933 IPv6-over-IPv4, for a total of four possible combinations...
So tun(4) is a way to get packets to userland while gif is a real tunnel
device encapsulating the packets and sending it to a remote tunnel
endpoint. The two things are totaly different and yes you could make IPsec
in userland over tun(4) but nobody is enough of a masochist to do that.
--
:wq Claudio
