Not remove interface when wpa_supplicant shuts down

Pavel Roskin proski
Mon Jun 7 14:13:01 PDT 2010

On Mon, 2010-06-07 at 19:41 +0100, Panagiotis Georgopoulos wrote:

> Sorry for not putting it correctly, yes the interface is not removed,
> it is just brought down, which reasonably -as you point out- removes
> the routes. However, this is still annoying because when the interface
> is brought down it loses its IP and all the related routes are removed
> and should be added manually. Plus, if I have wireshark capturing
> traffic on this interface it will whinge for the interface that was
> brought down. 

I suggest that you try to instruct wireshark not to exit.  Perhaps you
should talk to wireshark developers.  It would be a more valuable tool
if it could monitor all packets as soon as the interface goes up.

Routes can be added by a script.  Fedora would do it
using /etc/sysconfig/network-scripts/ifcfg-* scripts if the old style
network configuration scripts are installed, as opposed to

> So if I am debugging and want to run wpa_supplicant again, I have to
> manually bring it up, configure its IP address, add all the routes,
> execute wireshark to capture traffic on it and then run wpa_supplicant
> (which as you imagine becomes very time consuming and tiresome). If I
> don't do all this manually, and I just run wpa_supplicant, it will
> bring the interface up, but I still would have to add the IP address
> and routes later, plus I would not be able to capture all the initial
> packets that the interface will exchange with the Aceess Point in
> wireshark (because the interface will be brought up by wpa_supplicant
> and wireshark will not be able to capture traffic on this quickly).
> So, any ways to disallow wpa_supplicant or hostapd to bring an
> interface down when they are stopped?

I'd rather see features added to wireshark, which is a specialized tool
and is big already.  wpa_supplicant or hostapd should be kept simple, as
they are often run on embedded systems.

Pavel Roskin

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