I've been testing netman and discussing it with edbarx on this thread at fdn -
http://forums.debian.net/viewtopic.php?f=3&t=124343&sid=39afc987dc48172a6553bb0941d12461

netman connects but won't disconnect, and produces the following messages
in the terminal:

# click Disconnect first time:
Ignoring unknown interface wlan0=wlan0.

# click Disconnect second time:
ifdown: interface wlan0 not configured

If I try 'ifdown wlan0' in root terminal, I get the same messages. I have
to bring the interface down with 'ifconfig wlan0 inet down'.
And if I try running './backend 5' from /usr/bin/netman/ I get the same
messages.


Here's the output of 'ip a' under various circumstances (in order):

Interface down:
    wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast
state DOWN group default qlen 1000
        link/ether 00:1f:33:82:e4:8b brd ff:ff:ff:ff:ff:ff

Connect with netman:
    wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
        link/ether 00:1f:33:82:e4:8b brd ff:ff:ff:ff:ff:ff
        inet 192.168.1.101/24 brd 192.168.1.255 scope global wlan0
           valid_lft forever preferred_lft forever

Disconnect with netman:
    wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
        link/ether 00:1f:33:82:e4:8b brd ff:ff:ff:ff:ff:ff
        inet 192.168.1.101/24 brd 192.168.1.255 scope global wlan0
           valid_lft forever preferred_lft forever

My workaround (and quote from post on fdn)
ifup wants to see "allow" or "auto" associated with an interface. I tried
adding "allow-hotplug wlan0" to /etc/network/interfaces, but that didn't
help, so I removed it. Then I added it to the file in /etc/network/wifi
and added "source wifi/*" to interfaces, and that seems to fix the
problem. I can now connect and disconnect with the buttons in netman. And
'ifup/ifdown wlan0' works in root terminal now.

/etc/network/interfaces

    auto lo
    iface lo inet loopback

    source wifi/*        # I added this line

/etc/network/wifi/my-essid

    auto lo
    iface lo inet loopback

    allow-hotplug wlan0       # I added this line
    iface wlan0 inet dhcp
        wpa-ssid my-essid
        wpa-psk "my-secret-password"

Running devuan/angband/exegnu/jessie

-fsmithred