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Ovion

Member

Registered: 2013-02-24

Posts: 78

nectl-auto - scanning active or passive/revealing network names?

Hi,

I was wondering if the netctl-auto-unit scans actively for certain networks or passively. What I mean is: If someone would sniff the traffic of my wifi-card (by sitting in the same cafe etc.), would this person be able to say
1) if netctl-auto is enabled
2) which networks I want netctl-auto to connect to (e.g. because netctl-auto sends regular "Are you there, network xy"-requests, if there is no network)

Or is my wifi-card scanning for networks anyways and netctl-auto just takes the scan-results, looks for the networks wanted and initializes a connection in case of a finding without scanning actively?

Last edited by Ovion (2013-09-27 18:45:28)

Spider.007

Member

Registered: 2004-06-20

Posts: 1,175

Re: nectl-auto - scanning active or passive/revealing network names?

I am pretty sure you cannot look for a specific network; the only thing you can do is request a list of currently visible networks and possibly filter that for known matches. Also, I don't think you can sniff out other people who are also just looking at the list of available networks. Any specific reason you want to know this?

Ovion

Member

Registered: 2013-02-24

Posts: 78

Re: nectl-auto - scanning active or passive/revealing network names?

No specific reason, I was just wondering how netctl-auto works.

What about hidden networks? Do they appear in the scanned networks-list? Probably not, I assume. And would the netctl-auto increase the scan rate? In other words: would having netctl enabled reveal, that I'm present because with netctl-auto disabled my wifi wouldn't scan for networks regularly, but just be passive?

Spider.007

Member

Registered: 2004-06-20

Posts: 1,175

Re: nectl-auto - scanning active or passive/revealing network names?

I'm pretty sure that when a network is hidden; this only disables the active broadcasting when no-one is connected. If anyone is connected the ssid is included in plain text and thus easily discoverable. Netctl is simply a wrapper around wpa_supplicant; so you should check if list-networks uses active vs passive scanning. I would guess it uses active scanning as the documentation mentions 'completion' while a passive scan would never really complete.

Ovion

Member

Registered: 2013-02-24

Posts: 78

Re: nectl-auto - scanning active or passive/revealing network names?

So if I have a profile of a hidden network foo and I am somewhere else, I would regularly broadcast a message "foo, are you there?"?

To which documentation do you refer? Manpage?