I just installed Debian 8 the other day and initially had wifi dropping and not being able to reconnect without a reboot. After trying options like making sure power management was off, I cannot even connect to wifi on reboot, however.
The following posts are very similar, and I used them as a starting point, though could not see through to a resolution because of errors: rtl8821ae Wifi driver
rtl8812ae Wifi Connection Instability in Debian Jessie
jj@hostname:~$ uname -v
#1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19)
jj@hostname:~$ lspci -vnn | grep Network
03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821AE 802.11ac PCIe Wireless Network Adapter [10ec:8821]
jj@hostname:~$ sudo iwconfig
lo no wireless extensions.
wlan0 IEEE 802.11abgn ESSID:"dd-wrt"
Mode:Managed Frequency:2.412 GHz Access Point: E8:DE:27:F9:85:9E
Bit Rate=1 Mb/s Tx-Power=20 dBm
Retry short limit:7 RTS thr=2347 B Fragment thr:off
Encryption key:off
Power Management:off
Link Quality=70/70 Signal level=-12 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
eth0 no wireless extensions.
I followed the instructions to add "non-free" components and realtek firmware, but was unable to install linux-headers-generic
Package linux-headers-generic is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'linux-headers-generic' has no installation candidate
I confirmed the driver:
~# modprobe rtl8821ae
I did intall build-essentials and linux-headers-3.16.0-4-amd64, however. I installed wpa_supplicant, updated the .conf file as indicated, however:
~$sudo ifup wlan0
Unknown interface wlan0
~$ sudo /etc/init.d/networking restart
[ ok ] Restarting networking (via systemctl): networking.service.
~$ sudo dhclient wlan0
This just leaves 'wifi' saying 'connecting' without ever connecting.
Not sure what else to do. I had a different OS on this computer until yesterday and didn't have any connectivity issues, other machines are connected to wifi without any problems, so I don't believe it is an issue of the router or channel. Also:
root@hostname:/home/jj/# iwconfig wlan0 power off
Error for wireless request "Set Power Management"(8B2C) :
SET failed on device wlan0 ; Operation not supported.
just in case:
~# journalctl -u NetworkManager
...
<warn> interfaces file /etc/network/interfaces.d/* doesn't exist
...
UPDATE: My wifi connection is through an access point wifi router connected to another wifi router. I think the connection issue had to do with some settings there. I reset the AP wifi router and started from scratch, and am able to connect now. The only issue I have now is that if I plug into an ethernet connection, it will not return to a wifi connection after unplugging it unless I reboot. Will hunt around for a solution or post another question.
