diff --git a/entrypoint.sh b/entrypoint.sh
index 8ed72a4..16cc7a3 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -6,6 +6,10 @@ if [ "$#" -lt 1 ]; then
 fi
 unikernel=$1
 shift
+test -c /dev/net/tun || {
+	echo Cannot access /dev/net/tun >&2
+	exit 2
+}
 ip=$(ip a show eth0 | awk '/inet/{print $2}') || {
 	echo Could not determine ip address >&2
 	exit 2