In our village, our community can access the Internet over wireless
Access Points that use plaintext (no WEP nor WPA encryption, but some
captive portal that requests insecure login...). From this captive
portal, it looks as if the setup uses WLAN equipment from the Sinapore
based manufacturer ANTlabs. This gear apparently used here in the
Middle East to deploy commercial WLAN hotspots in hotels, ports, etc.
My wpi(4), iwn(4) and urtw(4) devices on OpenBSD 4.6-stable i386
connect without problem to those public APs with SSID "Dolphin
Village". Also, when scanning with 'ifconfig iwn0 scan', they detect
these APs on their respective channels (see sample output of urtw0 in
[1] below).
However, my two rum(4) devices, an old Linksys WUSB54GC and a brand
new D-Link DWA-110 do not detect any of the public APs on any channel
while scanning, but they find my private AP with SSID "CrossCom" (see
[2] below). After setting the SSID
'ifconfig rum0 nwid "Dolphin Village" up'
my client rum0 never seems to able to associate with any of the public
APs. Although both rum0 devices work fine when I have them associate
with my private AP using WPA. Also, both rum0 devices worked fine when
associating with other public APs.
On i386-current, I do not observe any difference nor improvement.
It looks as if the public APs or their beacons in our village are
somehow specific so that the rum() driver does not detect them (see
[3] below). The more obvious parameters in the beacon are the
regulatory domain list. A look into the source of rum(4) and friends
however did not trigger a better idea where to investigate next.
Has somebody else experienced similar problems with rum(4) and public
APs? Is there anything I should try next?
Thank you very much for any hint,
Rolf
P.S. to the maintainer of rum.4:
You may want to add the 'Alfa Network AUS036H' adapter to the list of
supported devices. It's an USB adapter with a reverse polarity SMA
connector for an external antenna. There are versions with 500 mW and
reportedly also with 1000 mW RF output power (although it looks as if
tweaking the source code is necessary in order to crank output power
above 100 mW).
I am not sure which version I have got, I'll have to open it up. I can
confirm reports that its receiver is markedly more sensitive compared
to other WLAN adapters I have on hand. Of course, an external antenna
also makes a difference. A stacked omni-directional vertical dipole
with 8 dBi gain came as an accessory.
[1] Alfa Network AUS036H
# dmesg
...
urtw0 at uhub0 port 1 "Realtek RTL8187" rev 2.00/1.00 addr 2
urtw0: RTL8187 rev 0x04, RFv2, address 00:c0:ca:31:41:a8
...
# ifconfig urtw0 scan
urtw0: flags=8a43<UP,BROADCAST,RUNNING,ALLMULTI,SIMPLEX,MULTICAST> mtu 1500
lladdr 00:c0:ca:31:41:a8
priority: 4
groups: wlan
media: IEEE802.11 autoselect (DS1 mode 11g)
status: active
ieee80211: nwid "Dolphin Village" chan 13 bssid
00:80:48:4a:9f:cd 44dB 100dBm
nwid CrossCom chan 12 bssid 00:08:a1:9c:32:c4 87dB 11M
privacy,short_preamble
nwid "Dolphin Village" chan 13 bssid 00:80:48:4a:9f:cd
44dB 54M short_preamble,short_slottime
nwid "Dolphin Village" chan 11 bssid 00:80:48:4a:a0:d1
38dB 54M short_preamble,short_slottime
nwid "Dolphin Village" chan 11 bssid 00:80:48:4c:d5:6d
24dB 54M short_preamble,short_slottime
nwid "Dolphin Village" chan 1 bssid 00:80:48:55:fe:b1
30dB 54M short_preamble,spectrum_mgmt,short_slottime
nwid "Dolphin Village" chan 1 bssid 00:80:48:55:fe:dd
21dB 54M short_preamble,spectrum_mgmt,short_slottime
inet 10.128.0.86 netmask 0xffff0000 broadcast 10.128.255.255
[2] Linksys DWA-110
# dmesg
...
rum0 at uhub0 port 3 "Ralink 802.11 bg WLAN" rev 2.00/0.01 addr 3
rum0: MAC/BBP RT2573 (rev 0x2573a), RF RT2528, address 00:24:01:9c:5e:45
...
# ifconfig rum0 scan
rum0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
lladdr 00:24:01:9c:5e:45
priority: 4
groups: wlan
media: IEEE802.11 autoselect (DS1)
status: no network
ieee80211: nwid "" 100dBm
nwid CrossCom chan 12 bssid 00:08:a1:9c:32:c4 112dB
11M privacy,short_preamble
[3]
# tcpdump -i urtw0 -nv -y IEEE802_11
13:23:24.710190 802.11: beacon,
caps=2041<ESS,SHORT_PREAMBLE,SHORT_SLOTTIME>, ssid (Dolphin Village),
rates 1M 2M 5M 11M 6M 12M 24M 36M, ds (chan 11), tim 0x00010000, erp
0x00, xrates 9M 18M 48M 54M, vendor 0x00037f01010000ff7f
13:23:24.780696 802.11: beacon,
caps=2041<ESS,SHORT_PREAMBLE,SHORT_SLOTTIME>, ssid (Dolphin Village),
rates 1M 2M 5M 11M 6M 12M 24M 36M, ds (chan 13), tim 0x00010000,
country 79 77 32 1 13 20, erp 0x00, xrates 9M 18M 48M 54M, vendor
0x00037f01010000ff7f
13:23:24.812699 802.11: beacon,
caps=2041<ESS,SHORT_PREAMBLE,SHORT_SLOTTIME>, ssid (Dolphin Village),
rates 1M 2M 5M 11M 6M 12M 24M 36M, ds (chan 11), tim 0x00010000, erp
0x00, xrates 9M 18M 48M 54M, vendor 0x00037f01010000ff7f
13:23:24.822451 802.11: beacon,
caps=2041<ESS,SHORT_PREAMBLE,SHORT_SLOTTIME>, ssid (Dolphin Village),
rates 1M 2M 5M 11M 6M 12M 24M 36M, ds (chan 11), tim 0x00010000, erp
0x00, xrates 9M 18M 48M 54M, vendor 0x00037f01010000ff7f
13:23:24.866454 802.11: beacon, caps=61<ESS,PRIVACY,SHORT_PREAMBLE>,
ssid (CrossCom), rates 1M 2M 5M 11M, ds (chan 12), tim 0x00010000, rsn
0x0100000fac020200000fac02000fac040100000fac0200000000, vendor
0x0050f20101000050f20202000050f2020050f20401000050f202
13:23:24.883206 802.11: beacon,
caps=2041<ESS,SHORT_PREAMBLE,SHORT_SLOTTIME>, ssid (Dolphin Village),
rates 1M 2M 5M 11M 6M 12M 24M 36M, ds (chan 13), tim 0x00010000,
country 79 77 32 1 13 20, erp 0x00, xrates 9M 18M 48M 54M, vendor
0x00037f01010000ff7f
