kern/121880: ath driver in 7.0 no longer honors 'monitor' mode

bob frazier bobf at
Wed Mar 19 20:40:03 UTC 2008

>Number:         121880
>Category:       kern
>Synopsis:       ath driver in 7.0 no longer honors 'monitor' mode
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Mar 19 20:40:03 UTC 2008
>Originator:     bob frazier
>Release:        7.0-STABLE (as of 3/2/2008)
FreeBSD BSDLaptop 7.0-STABLE FreeBSD 7.0-STABLE #0: Sun Mar  2 15:33:08 PST 2008

In 6.x the ath driver properly honored 'monitor' mode, shutting down transmit so that you could safely use tools like 'wireshark' without attempting to roam, associate with an access point, or transmit probe requests.

Using wireshark I verified that 'monitor mode' no longer works with the 'ath' driver.  This basically makes passive scans IMPOSSIBLE, including scanning for access points in the area without actually attempting to associate.

Again, the 'monitor' functionality worked properly in the previous release.  It no longer works in 7.0

a) issue the following command for hardware supported by the 'ath' driver
   ifconfig ath0 up ssid - monitor channel 1
   (alternately choose another channel on which an access point is known to be)

b) with an access point known to be on the monitored channel, run wireshark and capture radiotap headers in addition to normal traffic with 'promiscuous mode' chosen.

c) observe beacons AND response packets going to/from the atheros adaptor that is supposed to be in 'monitor' mode.



More information about the freebsd-bugs mailing list