troubleshooting
- From: stan <smoore@xxxxxxxx>
- Date: Sat, 26 Jul 2008 00:39:30 -0400
I will refrain from the specifics of hardware and such as I try to
describe the situation, but I'll gladly post as much as needed.
Basically I have a small home network (3 computers and a printer)
running wireless. I was having problems with the wireless drivers on one
system which just happens to run linux.
The only real symptoms I have right now are that the same system with
the driver problem is not playing well with the other children. The
driver problem concerns a TKIP error on some packets. For now I"m going
to work on the other, hopefully unrelated, problem. I'll try and start
with the simplest problem.
I can't ping the problem computer from my
laptop normally. I can ping the laptop from the problem computer
sometimes. At other times I can't ping anything from the problem
computer. In fact sometimes I can't ping the AP from the problem
computer. I've also discovered that the AP's mac is missing from the arp
table on the problem computer. So I manually put it back and I can get
things to run for awhile.
So at this point I can't ping the AP from the problem computer and the AP
mac is missing from the arp table. I've looked at the network with
tcpdump and wireshark and I can see the arp requests from the problem
computer but no reply from the ap. I can also see arp requests from my
laptop and the other computer on the net and they both get the expected
responses. So the laptop requests and gets a response from the ap while
the problem computer requests with no response.
My thinking about this is that there are several considerations.
1. The problem computer is generating malformed arp requests.
2. The generated requests aren't being received by the ap.
3. The ap is misconfigured.
Looking at one. I've looked at the packets and they appear to be
correct. The only difference I notice is that the problem machine is
generating a broadcast request while the laptop is using the known
ip/mac address. So I'm thinking the packets are probably OK.
Looking at two, the signal strength seems fine and one of the machines I
used to monitor the problem machines requests with tcpdump is farther
away. I have been in electronics for over 30 years and I've seen a lot
of strange progagation problems but I'm pretty sure the ap is actually
seeing the requests.
Looking at three, I can't find anything that looks like it could impact
arp requests from the wireless side. I've seen the ap respond to
broadcast requests so even though I couldn't find anywhere to turn that
on or off I don't find that a real strong contender.
My actual request here is for someone to tell me if I'm missing
something, or misunderstanding the big picture here. How about it? Any
ideas on what I could do next?
The ap is a Linksys WRT54G wireless router running the latest firmware
and I have no idea how to get past the web interface into the system to
actually see if the arp requests are being seen. I'm not using dhcp here
I use fixed ip addresses. I can ping the problem computer from the
router.
Even when I manually add the arp on the problem machine, it eventually
clears the table when it doesn't get any response to the unanswered
requests. When I reboot the computer it runs for awhile and then fails.
I can restore operation by restarting the network and manually adding
the ap mac to the arp table.
.
- Follow-Ups:
- Re: troubleshooting
- From: Bill Marcum
- Re: troubleshooting
- Prev by Date: Re: 192.168 - why?
- Next by Date: Re: 192.168 - why?
- Previous by thread: Duplicate pings
- Next by thread: Re: troubleshooting
- Index(es):
Relevant Pages
|
