I'm having a strange problem on a RPi 2 Model B. I just reformatted the sd card with the newest version of Raspbian and done all the sudo get update/upgrade stuff. I've plugged in an ethernet connection and a wifi-dongle. They both are operational. I have internet access from the ethernet cable.
In terminal, running
sudo ifdown wlan0
ifdown: interface wlan0 not configured
even if I have run
wlan0: flags=4099<UP,BROADCAST,MULTICASST> mtu 1500 ether 00:0f:60:07:fa:ef txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Why doesn't ifdown work (can I fix it)? It doesn't work for my eth0 connection either. Also my /etc/network/interfaces file seems a bit weird to me, the only line in it that's not commented is:
There is nothing in /etc/network/interfaces.d. The reason why I want to run ifdown is that I want to use the raspberry pi as a router and one of the steps in the guide I'm following says to use that. Either way, I'll need it to be functional in the future (and ifup outputs the same error message).
Notes: In the taskbar, hovering over the internet icon shows a tooltip: Connection to dhcpd lost. I don't know what it means, but Wicd Network Manager shows that I have access to both a wired network and I can see all of the wifi networks from the Wicd GUI. lsusb shows the wireless network adapter. iw list shows the normal stuff. dmesg | more shows the USB Receiver and normal stuff.