This happens a lot with one of my Raspberry Pis. I have a script which checks for an Internet connection and runs
ifup wlan0 when a connection is not present. Some of the things you could try:
- Rebooting the Raspberry Pi
- Checking that you have a valid IP address using
- Ensuring that you have power-saving features disabled on the dongle by adding
wireless-power off to your
ifup --force wlan0
Here's a script which runs every five minutes from cron:
#Script to check the network connection
#Check network connection
if /sbin/ifconfig wlan0 | grep -q "inet addr:" ; then
#Connection is good; do nothing
echo "$(date "+%D [%H:%M:%S]") Connection is up"
echo "$(date "+%D [%H:%M:%S]") Network connection down. Attempting to reconnect..."
sudo /sbin/ifup --force wlan0
If that is a wireless card power management issue, you can also have a look at WLAN disappears after some time.
Many wireless network cards don't support
wireless-power off option in
/etc/network/interfaces. To disable power management with a 8192CU module loaded, you can create a file
sudo nano /etc/modprobe.d/8192cu.conf with the following contents.
# Disable power management
options 8192cu rtw_power_mgnt=0