Forbes, Another thing to check, do you have any switches that do POE? Make sure you don't have a CAT5 wire with water getting inside and traveling all the way down into your switch and dumping water in there.
-Kurt Fankhauser ----- Original Message ----- From: "John Kingsley" <[email protected]> To: "WISPA General List" <[email protected]> Sent: Sunday, August 01, 2010 9:42 PM Subject: Re: [WISPA] I NEED HELP > Forbes Mercy wrote: >> Wow very interesting hypothesis since it happened right after a >> lightning storm with heavy rain. Trouble is I shut off all six >> backhauls and started turning them on one by one until I had a "IP >> conflict" warning then turned that one off, the IP conflict happened >> again, yes I did arp -d to clear the bouncing out of it but then it >> happened on a different tower, I just can't seem to find it and yes >> we're way too large to be bridged, that was our summer project to become >> routed but that doesn't help today. It's a great idea but I have 54 >> AP's so I don't know where to start. >> >> Forbes > > Hi Forbes, > > I agree with Kurt (below), sounds like a layer2 issue. > > I had similar issues in the past, after storms. > Typically a dumb switch on the network goes "bad", > and causing arp problems. > > Now ... the hard part... how to find which device > is causing the problem? > > Some ideas: > > 1) Try pinging a device on your network that you know is working fine. > If you can't reach it, then good! Now immediately dump your arp > table and look for the mac address of the ip you are trying to ping. > This mac might be the "bad" device. Or at least it might point in the > right direction (if you're doing proxy-arp on some of your links > then the "bad" device may be located on the other side of this mac). > > 2) Start up wireshark (or tcpdump) and watch the arp packets. > Look for a mac address which show up a lot. Dump your arp table > and see what ip addresses match this mac address. > Look for arp table entries which have the same mac, > which is not normal (unless you're doing proxy-arp). > > Doing this may give some clues. If you have many different > types of devices on your network, use one of the mac lookup tools > to find out what kind of device it is, given the mac address: > http://www.coffer.com/mac_find > This might help narrow down the device. > > 3) Watch the stats on the radios to see which clients or radio links > have high packet counts. If there is an arp storm, this may > help you narrow down which client is causing the storm. > (ideally do it at a time when your network is normally quiet, like early > morning) > > 4) Focus on sites where you have dumb switches installed. > I find these dumb switches often go berserk when zapped. > > 5) Focus on sites that have had problems in past storms. > Chances are higher that they are causing your current problem. > (in my case these sites are the ones which don't have shielded cat5 or > are poorly grounded) > > 6) If your network covers a large geographical area and > the storm was localized then focus on looking for the bad > device in the area where the storm hit hard. > > Good luck. > > John > >> >> On 8/1/2010 11:09 AM, Kurt Fankhauser wrote: >>> Forbes, >>> >>> I remember seeing something similar to this on the list a few months >>> back. >>> Turned out he guy was running a bridged network and water got into the >>> Ethernet connector on a Bullet and was causing Layer2 broadcast storms >>> on >>> the network. Very similar results to what you are reporting. >>> >>> Kurt Fankhauser > > > -------------------------------------------------------------------------------- > WISPA Wants You! Join today! > http://signup.wispa.org/ > -------------------------------------------------------------------------------- > > WISPA Wireless List: [email protected] > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ > -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
