How To Check TUN/TAP or PPP is Enabled

To check if TUN/TAP is enabled on your server, type this

cat /dev/net/tun

If the result is

cat: /dev/net/tun: File descriptor in bad state

your module has been enabled on your server.

To check if PPP is enabled, do this

cat /dev/ppp

if you receive message

cat: /dev/ppp: No such device or address

the module has been enabled successfully.

Source:
http://forum.host1plus.com/vps-support/428-how-check-if-tun-tap-ppp-enabled-your-vps.html