I have set etc/network/interfaces to auto start wlan0. that is working fine.
if I use 'ifdown wlan0' or 'ifconfig wlan0 down' the interface is brought down, but I cannot restart it.
if after boot I use 'ifdown wlan0 && ifup wlan0' I get an error message for ifup and iwconfig shows 'no wireless extensions' for wlan0, wifi0, lo, and eth0.
inxi -xF show wlan0 status:down
How do I restart wlan0 without rebooting? I also tried ifup wlan0=wlan0 to no avail.

I could not previously post this. On Oracle's suggestion I dropped the slash in front of etc

hmmm.... is this an internal device or a usb device?

I have had trouble in the past with ifup/ifdown. try

ifconfig wlan0 up

this is internal on a T23 Thinkpad
it is an Intersil Prism 2.5/3, driver hostap
I tried ifconfig wlan0 up; that didn't work either.
Curiously inxi shows two interfaces for the same card: wifi0 and wlan0; same mac address

have you tried bringing up wifi0?

Yes.
with ifup wifi0, the message is: Ignoring unknown interface wifi0=wifi0.
with ifup wlan0 the message is: ifup: interface wlan0 already configured
with ifconfig wifi0, the message is: SIOCSIFFLAGS: No such device
with ifconfig wlan0, the message is: SIOCSIFFLAGS: No such device

Hi, guys.
This is still a problem.
Anyone have any ideas?

It looks like ifdown wlan0 and ifconfig wlan0 down are turning off the wireless card. I have no physical way to turn it back on. with the legacy Windows program, Fn+F5 would turn on the wireless but that was dependent on the IBM software, which is not present with the antiX 15 base install.

does

rfkill list all

show anything usefull? soft-block maybe?

Off the desk - will try later today

rfkill list all does not show anything

Still struggling with this problem. Any ideas?

I am attempting to update the firmware on the wireless card and will let you know if that fixes the problem.

Just a thought, but have you tried re configuring the card with ceni or wicd?