[MLB-WIRELESS] Smart Amps??

[Jason Tedesco]

To get around the signal loss of using LMR-Cable down to your AP or linux box, has anyone purchased an amp or smart amp?  
Someone was telling me you could put a smart amp in a box say on your antenna mast, run cable from the smart amp down to your AP, say in your roof/room, and the smart amp will still pump out 1 watt of power no matter what the signal loss is.  Going price around $1000-$1500.  Can anyone confirm this, or had any experience with any kinds of amps with wireless devices.

Cheers,
Jason

-----Original Message-----
From: Craig Sanders [mailto:cas at taz.net.au]
Sent: Tuesday, 21 January 2003 15:29
To: melbwireless
Subject: Re: [MLB-WIRELESS] Dlink AP security hole etc.


On Tue, Jan 21, 2003 at 01:33:23PM +1100, paul van den bergen wrote:
> to do a firmware update on these boxes, do you need to be logged into
> the AP interface?  or can you flash them without anything other than
> seeing them on stumbler (etc.)
> 
> in other words, does the "security flaw" require authorised (yeah,
> well) access?
> 
> either way, has anyone sought to inform those who consider this an
> issue (CERT, for example) that this is a problem?

i don't know, but it's of serious concern to me.  i'm astounded that
dlink could possibly think that it was OK to release something with such
a wide-open gaping security hole.  i'm hoping that it's not as bad as
the reports indicate.

i'm also seriously considering replacing my dlink 900AP+ with a PCI or
PCMCIA card in my linux box - and accept the signal loss of ~15 metres
of LMR-400 cable.  at least i can be confident that it is secure....and
i'll have full control over the routing and bridging capabilities.

i have another node (a leafnode where it doesn't matter much if it goes
down for a day or so until i get around to resetting the config) where i
can use the 900AP+, but i don't think i want to use it on a router node
any more.


since i upgraded to v2.5 firmware on my dlink 900AP+, i've also noticed
the following problems:


1.  it doesn't seem able to route between two wireless clients.  i have
an AP is on 10.10.48.114, connected via ethernet to my firewall on
10.10.48.113.

at the moment, i'm building a few (debian based) wireless boxes for
people in the innernorth area, so i have a few wireless nodes to test
things with.

i have a laptop (10.10.48.115), and barry's machine "antifsck"
(10.10.48.119) as wireless managed clients of the dlink DWL-900AP+.
they can each talk to the AP, and to my firewall box (which is also my
debian mirror).  they can't, however, talk to each other.  

if i ping from say the laptop to antifsck , then tcpdump shows the arp
request going out the wlan0 interface, but it never gets seen by
antifsck.  AFAICT, it's just being blocked by the AP.  ditto for any
traffic from antifsck to the laptop.  not good.

i don't know if v2.4 does this - i didn't have two clients to test it
with at the time.


2. the second major problem is that with v2.5, the AP seems to forget
about clients if it doesn't hear from them for a while.  

if i leave a ping running, say one ping every 120 seconds, then it's
fine.  ditto if i run ntp or rwho or some other periodic broadcast.

...but if there's no traffic at all for a while(*) then the AP just
doesn't see the client any more, and the only way to get it to see the
client again is to either reset the AP or restart the wlan interface on
the client (i.e. "/etc/init.d/pcmcia restart") to force it to
re-asssociate with the AP.

(*) i don't know how long "a while" is.  it's at least 5 minutes.  i
haven't had the time to find out exactly how long it is.

i'm not sure if this was a problem with v2.4 or not - the only client i
had was running rwhod and ntpd so there was regular broadcast traffic
every couple of minutes to keep the link alive.  i guess if it was a
problem, i would have heard about it by now from other users.




i should downgrade to 2.4 firmware and see if the problem goes away.
but then i lose the useful ability to set the Tx power to 19dbm rather
than the puny 13-15dbm.

craig

-- 
craig sanders <cas at taz.net.au>

Fabricati Diem, PVNC.
 -- motto of the Ankh-Morpork City Watch

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