Failure to connect to hidden SSID with WPA Supplicant on Debian?

Question

I asked a similar question the first time I did this. It can be found here.

I tried to streamline the process this time. I got the hardware ID of my WiFi-Dongle on my windows machine, and searched for the driver. The dongle is a EW-7811Un Edimax dongle. Looking around, I found that my kernel should already support this out of the box.

Keep in mind I have NO connection until I get this WiFi working, so I've been transferring files for my architecture/distro/version by USB then unpacking and installing them. I've been following this guide.

What I've done so far:

1) Installed WPA_Supplicant for my architecture and version of Debian.

2) Installed Wireless Tools for my architecture and version of Debian.

3) Updated the interface file to exactly mirror the following with my information

 auto wlan0
 iface wlan0 inet dhcp
    wpa-ssid MySSID
    wpa-psk myHashedPSK

4) Exported the output of wpa_passphrase myssid my_very_secret_passphrase to /etc/wpa_supplicant/wpa_supplicant.conf

After rebooting with my dongle in the USB slot, iwconfig returns no connections. In fact as far as I can tell nothing has changed from the stock install of Debian.

I should mention that my SSID is hidden. I realize that it is just the "warm-and-fuzzies" to hide SSIDs, but it's not my choice whether or not it is, and I do not have the permission to change it.

What am I doing wrong? Is there something I've missed?

Solution

You need to use scan_ssid to connect to hidden SSIDs.

In your configuration it will be:

auto wlan0
iface wlan0 inet dhcp
   wpa-ssid MySSID
   wpa-psk myHashedPSK
   wpa-scan-ssid 1

In wpa_supplicant.confit is:

network={
    ssid="MySSID"
    scan_ssid=1
    psk=myHashedPSK
}

It should be enough to configure the SSID properties either at /etc/network/interfacesor /etc/wpa_supplicant/wpa_supplicant.conf.

From wpa_supplicant.conf manual:

scan_ssid: SSID scan technique; 0 (default) or 1. Technique 0 scans for the SSID using a broadcast Probe Request frame while 1 uses a directed Probe Request frame. Access points that cloak themselves by not broadcasting their SSID require technique 1, but beware that this scheme can cause scanning to take longer to complete.