USB Wi-Fi dongle listed in lsusb, wlan0 OK in ifconfig, but no address and all RX dropped

Question

I am currently trying to make my USB dongle work on the Pi.

I have seen a lot of posts about this dongle, and I am sure it will work, but following all the posts I have found never gives me the same result.

First, I checked lsusb:

pi@retropie ~ $ lsusb
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. 
Bus 001 Device 004: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n

So far, so great... Then, ifconfig:

pi@retropie ~ $ ifconfig
eth0      Link encap:Ethernet  HWaddr b8:27:eb:3a:1c:e9  
          inet addr:192.168.1.6  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1728 errors:0 dropped:0 overruns:0 frame:0
          TX packets:242 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:92627 (90.4 KiB)  TX bytes:34935 (34.1 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:2 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:100 (100.0 B)  TX bytes:100 (100.0 B)

wlan0     Link encap:Ethernet  HWaddr e8:4e:06:1c:1b:94  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:41 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

Looks like there is something wrong there... So, I followed this post: USB WiFi adapter being detected but no connection

I changed /etc/network/interfaces to:

auto lo

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp

Then, I rebooted, but nothing changes.. Still the same output from ifconfig.

Any idea what I am doing wrong?

EDIT: as suggested, I added: wpa-ssid "myssid" wpa-psk "********" right below iface wlan0 inet dhcp

But

wlan0     Link encap:Ethernet  HWaddr e8:4e:06:1c:1b:94  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

Only difference is that I have no dropped packets.. But still not connected

Answer 1

In your /etc/network/interfaces file what you have is

auto lo : auto specifies that your that the interface lo which stands for loopback is going to be up automatically at boot.

iface lo inet loopback: this is also part of stanza of lo

iface eth0 inet dhcp : here, you are telling eth0 interface is going to be automatically configured via dhcp

If I were you I would also add auto eth0 | allow-hotplug eth0 above iface eth0 inet dhcp

Now we came to wlan0 stanza.

Start with adding auto wlan0 on top of that stanza for getting the interface up on boot if you don't want to do it manually.

The main thing you are doing wrong is you didn't specify anything to connect, you can't expect Pi to enter SSID or password with its own judgment.

So you have to add :

wpa-ssid "yourssid"
wpa-psk "yourpassword"

right below iface wlan0 inet dhcp

For more information : https://wiki.debian.org/NetworkConfiguration