LINUX bash - ifconfig + if statment not working

I have follow script:

#!/bin/sh
if ifconfig tun0; then
echo tun0 active
else
echo tun0 inactive
fi

When I run this script on a user - worked, but when I run the script on startup with crontab it always come tun0 inactive but tun0 are active..

can some one help me on my problem?