Archived from groups: alt.internet.wireless (
More info?)
On Sun, 18 Jul 2004 14:29:00 +0200, "Frank" <frank@nospaminter-iq.nl>
wrote:
>> Can you ping the router from the W98 machine?
>Yes. No problem.
Ok, let's walk through a troubleshooting exercise. If you can ping
the local router, then it's highly likely there's something wrong
between the router and the ISP. We start by pinging oneself, then the
router, then the ISP's gateway, then something on the internet. Do
this step by step and do not blunder on to the next step until
everything works.
1. Thyself first. Open a DOS window with:
Run -> CMD (or command for Win 98/ME)
Just about everything that follows will be done from this DOS window.
Run:
ipconfig
The IP address is your IP address, the gateway address should be that
of the router. If it hangs, your machine is having a problem
obtaining an IP address (DHCP failure). If it shows 0.0.0.0 for the
wireless card, you didn't get an IP address. Try again with:
ipconfig /renew (W2K or XP)
ipconfig /renew_all (W98/ME)
If the address is 169.254.xxx.xxx, then DCHP is working, but failed to
get an IP address for some reason. Usually that's because the router
was off when you booted the computah. Just run:
ipconfig /renew
followed by:
ipconfig
and you should see valid IP addresses.
Please note that all the above assumes that you have a good radio
connection and a proper WEP key. If not, turn off WEP or WPA for the
rest of the test. If you then get a valid IP address, then you have
one of the mysterious WEP key compatibility problems which defy
explanation.
If you still don't get an IP address with XP, and you just happen to
be recovering from a virus or spyware, try:
http://www.snapfiles.com/get/winsockxpfix.html
which seems to fix some connection problems. It can't hurt.
2. Next, run:
ping your_ip_address
If that fails, look for stuff on your computah such as, firewall
issues, proxy server issues, broken IP stack, network properties
configuration issues, operating sniffers, etc.
3. Next, ping the gateway IP address with:
ping gateway_ip_address
If that fails, and you know that you have a good radio connection,
then you have an impossibility. You can't have the router deliver a
DHCP address *AND* not have it respond to a ping. Actually, I have
seen this once, where I screwed up the firmware update on a Linksys
BEFSR41 router. It would deliver a DHCP address, but not do anything
else. If this happens to you, reset your router and start over.
Notice that I did NOT use a web browser for testing. There are far
too many ways to screw up the settings in a browser and have things
fail. The most common one is to enable "automatically detect
settings" in the:
Control Panel -> Internet Options -> Connections -> LAN settings
Unless you have a proxy server, don't enable it. It usually just adds
about 30 seconds to the boot time, but often finds someone's proxy
server on the network and declares that to the the path to the
internet. University wireless systems also tend to use proxy servers
but are usually configured manually, not automagically.
3. If you can ping the gateway, you should be able to ping your WAN
IP address. To find this, connect to your wireless router with a web
browser, login, and go to the "status" page. Scribble down the IP
addresses or just print the page. These numbers may change over time,
but will probably be stable for the duration of the test. If the
numbers are all 0.0.0.0, you have a configuration issue between your
router and your ISP. Check your settings, wiring to the DSL or cable
modem, status lights on the router WAN port, status lights on the
router.
If you have what looks like valid IP addresses, run:
ping YOUR_WAN_IP_ADDRESS
If that fails, you may have turned off a router setting that disables
responding to ping (or ICMP ECHO). Don't worry about it and just
blunder onward.
3. Next in line is the gateway address of the ISP. This is important
because it proves that you can actually send and receive packets
through the DSL or cable connection. Run:
ping WAN_GATEWAY_IP_ADDRESS (or default gateway)
That's the gateway as shown on the Status page, not the one on your
computah belched by IPCONFIG. If that fails, you may have a screwed
up cable or DSL modem/bridge, or your ISP is out to lunch. I would
give their support a call and ask them to runs some diagnostics on
your connection. For DSL, ask for an ATM ping test from the DSLAM.
4. Assuming you can ping the ISP's router (the gateway), try
something on the internet by IP address. One of the DNS servers
listed on the status page are a good start. Also try well known
servers by IP address.
5. Assuming you can ping an assortment of servers on the internet by
IP address, we now move to testing DNS. Instead of pinging by IP,
run:
ping www.yahoo.com
by name. Not every web server returns pings, so if one doesn't work,
try another. If that consistantly fails with an "Unknown host" error,
then DNS is not resolving names into IP addresses.
Lots of places for DNS to screw up. W2K and XP are stupid in that
they cache both successful and unsuccessful DNS lookups. You can
demonstrate the problem by unplugging the ethernet cable between the
computah and the router, opening a web browser, and trying to load a
new web server page (one you haven't looked at before and is not in
the explorer cache). Now, plug the router back in. You can probably
browse any web page EXCEPT the one that failed when it was unplugged.
That's because XP remembers the failed lookup and continues to
remember that it had failed even after a connection is restored.
http://www.sanx.org/tipShow.asp?articleRef=200
Most wireless router DHCP server have a DNS cache to reduce DNS lookup
traffic. You'll find that IPCONFIG points to the router as the DNS
server instead of the ISP's DNS servers. That's fine if it's working.
It's hell when it doesn't respond correctly to IP changes from load
balancing servers. You can bypass the problem by inscribing the IP
addresses of your ISP's servers into the:
Control Panel -> Network -> Wireless -> TCP/IP -> Properties -> DNS
settings. If that works, but pointing to your router does not, your
router firmware has a problem.
Other causes of DNS failures are denial of service attacks on the
ISP's DNS servers, heavy network traffic, screwed up TCP/IP stack on
the computah, and the usual software in the middle (personal
firewalls, Windoze firewall, proxy servers, etc). Sometimes, erratic
DNS responses can be traced to the primary DNS server being down for
maintenance, and the computah taking its time switching to the
secondary. I'm not sure what algorithm Windoze uses, but whenever I
accidentally mistype the primary DNS server IP address, I get long
delays and timeouts on using the secondary.
Anyway, there you have the basic troubleshooting exercise. Start at
your end and systematically walk the packets through every device
until it gets to the internet. Where the packets stop, is usually the
problem.
Incidentally, when you say "no internet", I hope you don't have IE6
set to "work offline". That would be too easy. If ping and DNS work,
IE should also work.
--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
05lf0h4hfj8tebdnag6h39rgon7972241@4ax.com...
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