Thank you for that hint, I have already seen that article and went through the initial part (that one without the coding examples) and also managed to create a second tun device. However, the client I use seems to clone the TUN device itself, that's probably why I cannot type or choose another device rather than /dev/net/tun or several tap devices (it just does not allow to continue identifying any other configuration as wrong). Unfortunately none of the TAP devices works (might be because of server side configuration of the customer, I don't know). So my only option is /dev/net/tun. (The phion/barracuda vpn client is used - one terminal based I got from the customer - myself I was not able to download some client from the website there). If anybody knows if there is another compatible client that works, would probably help.
But what I think: Somehow it seems that VMWare player is locking the dev/net/tun device that it can't be cloned by other processes what the intention of that device is. Just my impression - I am missing the knowledge how to proove that.
I have read again through the article - even the part with the coding. I also used openvpn to create a tun device but I still cannot choose that interface - pretty sure that the vpn client wants to clone the device itself. In my opinion the installed vmware player - after adding his portion to the kernel - is blocking device cloning.
