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[Karlnet] KarlBridge/Router Notes

To: "'Karlnet Mailing List'" <karlnet@wispnotes.com>
Subject: [Karlnet] KarlBridge/Router Notes
From: "Justin W. Pauler" <jwpauler@air-q.com>
Reply-to: jwpauler@air-q.com,Karlnet Mailing List <karlnet@WISPNotes.com>
Date: Mon, 2 Feb 2004 10:33:26 -0600
List-post: <mailto:karlnet@WISPNotes.com>
Hello Everyone...

We've got some KarlNet units at different HotSpot locations, so far I am
impressed with the multitude of features and options that I have seen.
However, as of recent, I've noticed a few bugs/annoyances, call them what
you will, but I wonder if anyone has seen any of this before.

First, a little about my setup. We're using KarlNet KarlBridge/Router units,
two PCMCIA slots and two ethernet connections. These units are acting as
HotSpot Authentication bridges, therefore we are not using the PCMCIA cards.
The setup is fairly simple, we have our external network (public IP address)
connected to the first ethernet interface and a 10/100BaseTX switch
connected to the second ethernet interface which connects in 10-15 dumb
access points. These access points are simple "dumb" Wireless bridges (they
don't even have an IP address!).
        
        IE:

                *INTERNET*  ->  {KARLNET) -> [SWITCH] -> ACCESS POINTS

This setup is being used for a test right now, but I would assume could be
valid for sharing one KarlNet board over several different access points. I
don't see anything technically wrong with it as long as you don't overload
your external interface or run out of DHCP addresses.

Now, as for things I've noticed:

        --

        On starting the KarlNet unit, everytime it finishes booting it sends

        out a major ARP broadcast across the internal network. Using WinDump
        to watch the packets, I see:

                "arp who-has 10.100.1.x tell 10.100.1.1"
                                                        ^^^ KarlNet
Interface #2 address

        It sends this arp request to every host in the DHCP range I have
specified,
        in this case, it sends an ARP to 10.100.1.25 though 10.100.1.250.
I'm 
        assuming this is normal as the unit is checking to see what DHCP
        leases are alive and left hanging since the last reboot. 

        Comments?

        --

        I've been playing with this units for a few weeks and have noticed
        what I call, "blackouts". 

        The board will be working great for a long period (this last time
for 13
        days straight) and show no signs of trouble. After a long period of
inactivity,
        a weekend for example (this unit is setup in a office complex), when
someone
        tries to use it for the first time, it appears to be dead. The unit
will assign
        a DHCP address (release / renew works too), the board has power, it
responds to
        ICMP pings, and SNMP is even running, but not any type of
redirection. The last
        time this event happened, I had the opportunity to watch the traffic
with WinDump
        and sure enough, the board is never responding to an HTTP request.
My laptop sends
        it out, but nothing is ever received back from the KarlNet board.

        Now, after explaining this scenario to a few third-party people and
to some KarlNet
        Tech Support, the first thought was maybe just a laptop problem. Ok,
sounds resonable.
        So, I waited until it happened again and tried to hit a webpage; no
redirection. I
        immediately went to my desktop, logged onto the KarlNet unit and
issued a Reboot and
        when I saw it come alive again, went to the laptop and hit 'F5' in
Internet Explorer
        (to make it appear as just another HTTP request). I was forwarded
directly to the login
        page just like it was supposed to.

        Ok, so the second idea was power related. After checking with
KarlNet and looking over
        my power supplies, it seems that I was low on power (sending about
9w to the units when
        they really need 11w). So I swapped out a power supply with a 15v
1000MA unit,
        which by my calculations, should be 15w into the unit. That was 13
days ago. From that
        point our unit has been working great, not a single sign of a
problem, until this morning.
        I came in from the weekend and it refused to redirect me. I once
again repeated the above
        testing (just hitting 'F5' after rebooting it) and it came alive as
usual, just like
        nothing happened.

        I did take a few moments to look around in the statistics to see
what might be the cause,
        and the only thing I found odd was the DHCP lease list. It showed
that nearly all of my
        addresses had leases on them, but yet, none of those units were
accessing the network, nor
        were they pingable from that segment. The default time on the leases
is about 4 hours from
        what I see, and I know for a fact from looking in the logs on our
RADIUS server that 225
        people did not authenticate or even try to authenticate during that
period.

        Any ideas, thoughts, comments or suggestions?

        --

As I said above, so far I am impressed with KarlNet hardware and I would be
willing to use them much more than I am now, if I could get the units to
stay alive!

--
Justin W. Pauler
Network Administrator
Air-Q WiFi Corporation
E-Mail: jwpauler@air-q.com
WWW: http://www.air-q.com
Phone: (225) 923-1034 x87
Fax: (225) 923-1036 
AIM: AirQ Support
    



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