On Wed, Oct 15, 2003 at 05:52:03PM +0200, Dries Schellekens wrote:
> On Wed, 15 Oct 2003, redmar wrote:
>
> > > > I've successfully added the tap device with these files to my 3.3 >
> > stable box,
> > >
> > > Why do people need this device? Isn't it the same as tun(4)?
> >
> > tun is network layer, tap is datalink layer.
>
> What is wrong with bpf(4)?
>

We already had that discussion once around 3.0.

From the manpages:

bpf -> Berkeley Packet Filter
The Berkeley Packet Filter provides a raw interface to data link layers
in a protocol-independent fashion. All packets on the network, even
those destined for other hosts, are accessible through this mechanism.

tap -> Ethernet tunnel software network interface
The tap interface is a software loopback mechanism that can be loosely
described as the network interface analog of the pty(4), that is, tap
does for network interfaces what the pty driver does for terminals.



> > I'm for example using the tap device for a bridged VPN with OpenVPN.

One reason is probably also that OpenVPN does not have a bpf support.
Last but not least I ported it becasue of a simulator.

--
:wq Claudio