internet access fails

I need help configuring my cable modem and router and Linux
box. Something has gone wrong, and I do not fully understand
how everything connects togather.

This works OK (picture requres fixed width font)

+------------+
+-------+ | AirLink | +-----------+
cable----+ cable | | AR315W | | WindowsXP |
| modem +----+ router/hub +---wire----+ computer |
+-------+ +------------+ +-----------+

This also works OK
+------------+
+-------+ | AirLink | +-----------+
cable----+ cable | | AR315W | | WindowsXP |
| modem +----+ router/hub | wireless> | computer |
+-------+ +------------+ +-----------+

This also works OK
+------------+ +-----------+
+-------+ | AirLink +---wire----+ WindowsXP |
cable----+ cable | | AR315W | | computer |
| modem +----+ router/hub | wireless> | |
+-------+ +------------+ +-----------+

With this last configuration, ping works for 192.168.1.1
(probably the router gateway?) and 192.168.1.100 (the wire
from the router to the computer) and 192.168.1.101 (the
wireless connection)

Then when I added a second computer, the second computer
is extremely slow finding one or two URLs, then it fails to
find any further URLs.
http://abcnews.go.com/ takes almost a minute
http://www.google.com/ is not found at all
ping google.com returns unknown host

From the Linux box, "arp -a" returns only the gateway.

My son thinks the Linux box cannot find the DNS server.
Is that possible? What commands can I enter from a terminal
to determine such things?

+------------+ +-----------+
+-------+ | AirLink +---wire----+ WindowsXP |
cable----+ cable | | AR315W | | computer |
| modem +----+ router/hub + wireless> | |
+-------+ | | +-----------+
| |
| | +-----------+
| +---wire----+ Fedora |
+------------+ | core 3 |
| Linux |
+-----------+
The Linux box is assigned 192.168.1.102 and can be pinged from
the Windows box. The Linux box can ping the gateway 192.168.1.1
The Linux box cannot ping either of the Windows addresses.

Does anybody know of an on-line set of step-by-step instructions
for setting up RedHat/Fedora ethernet?

Since the WindowsXP connects to the internet OK, I would guess
that the modem and router are OK, and my problem is within the
Linux box.

I have searched google. I have spent hours searching google.
Google finds several simple tutorials. But it finds nothing
of a troubleshooting nature. I have also searched this newsgroup
back for the last two weeks, and I find nothing there.

Tnx,
Charles

Charles wrote:

>
> Since the WindowsXP connects to the internet OK, I would guess
> that the modem and router are OK, and my problem is within the
> Linux box.
>
> I have searched google. I have spent hours searching google.
> Google finds several simple tutorials. But it finds nothing
> of a troubleshooting nature. I have also searched this newsgroup
> back for the last two weeks, and I find nothing there.
>
> Tnx,
> Charles

Check your resolve.conf for DNS nameserver as;

resolve.conf
nameserver 192.168.1.1

You IP may be different. At least that's how Slackware does it.

--
Robert - slackware

Charles wrote:

> http://www.google.com/ is not found at all
> ping google.com returns unknown host
Test using "host" rather than "ping". That way you are only testing DNS
lookup.
>
> From the Linux box, "arp -a" returns only the gateway.
> My son thinks the Linux box cannot find the DNS server.
> Is that possible?
Yes.
> What commands can I enter from a terminal
> to determine such things?
As another poster suggested, start by looking at the contents of
/etc/resolv.conf.

> The Linux box is assigned 192.168.1.102 and can be pinged from
> the Windows box. The Linux box can ping the gateway 192.168.1.1
> The Linux box cannot ping either of the Windows addresses.
Do you have a firewall turned on? If so, is it blocking ICMP packets?
Networking tutorials should tell you how to interpret the output of
iptables -L.
> Since the WindowsXP connects to the internet OK, I would guess
> that the modem and router are OK, and my problem is within the
> Linux box.
Probably.
>
> I have also searched this newsgroup
> back for the last two weeks, and I find nothing there.

Questions like this do get posted periodically, and answers usually
contain general advice you could use.

Other things you could do:

- look at the IP routing table, route -n (the -n disables reverse DNS).
"ip route" if you don't have route.
- while pinging the Windows box, use tcpdump (or other packet sniffer)
to see if the Linux box is sending out an ARP and if the Windows box is
replying.
- if you feel fairly safe behind your firewall, turn firewalling on the
Linux box off for a few minutes & try a couple of things. See if that
makes a difference. Then turn it back on while you figure out what
happened.

/etc/resolv.conf is the location of the dns servers.

Can you ping actual addresses
ping 216.239.57.147

If that works you have dns problems. If not you have routing problems.
If dns, look at /etc/resolv.conf and see if the nubers there make sense.

Ping those addresses and see if they respond.

If routing problems, look at an publish your route map
route -n
etc.

Charles <(E-Mail Removed)> writes:

>I need help configuring my cable modem and router and Linux
>box. Something has gone wrong, and I do not fully understand
>how everything connects togather.

>This works OK (picture requres fixed width font)

> +------------+
> +-------+ | AirLink | +-----------+
>cable----+ cable | | AR315W | | WindowsXP |
> | modem +----+ router/hub +---wire----+ computer |
> +-------+ +------------+ +-----------+

>This also works OK
> +------------+
> +-------+ | AirLink | +-----------+
>cable----+ cable | | AR315W | | WindowsXP |
> | modem +----+ router/hub | wireless> | computer |
> +-------+ +------------+ +-----------+

>This also works OK
> +------------+ +-----------+
> +-------+ | AirLink +---wire----+ WindowsXP |
>cable----+ cable | | AR315W | | computer |
> | modem +----+ router/hub | wireless> | |
> +-------+ +------------+ +-----------+

>With this last configuration, ping works for 192.168.1.1
>(probably the router gateway?) and 192.168.1.100 (the wire
>from the router to the computer) and 192.168.1.101 (the
>wireless connection)

>Then when I added a second computer, the second computer
>is extremely slow finding one or two URLs, then it fails to
>find any further URLs.
> http://abcnews.go.com/ takes almost a minute
> http://www.google.com/ is not found at all
> ping google.com returns unknown host

>From the Linux box, "arp -a" returns only the gateway.

>My son thinks the Linux box cannot find the DNS server.
>Is that possible? What commands can I enter from a terminal
>to determine such things?

> +------------+ +-----------+
> +-------+ | AirLink +---wire----+ WindowsXP |
>cable----+ cable | | AR315W | | computer |
> | modem +----+ router/hub + wireless> | |
> +-------+ | | +-----------+
> | |
> | | +-----------+
> | +---wire----+ Fedora |
> +------------+ | core 3 |
> | Linux |
> +-----------+
>The Linux box is assigned 192.168.1.102 and can be pinged from
>the Windows box. The Linux box can ping the gateway 192.168.1.1
>The Linux box cannot ping either of the Windows addresses.

>Does anybody know of an on-line set of step-by-step instructions
>for setting up RedHat/Fedora ethernet?

>Since the WindowsXP connects to the internet OK, I would guess
>that the modem and router are OK, and my problem is within the
>Linux box.

>I have searched google. I have spent hours searching google.
>Google finds several simple tutorials. But it finds nothing
>of a troubleshooting nature. I have also searched this newsgroup
>back for the last two weeks, and I find nothing there.

>Tnx,
>Charles

On Sun, 02 Jan 2005 16:21:01 -0600, Charles wrote:

> Then when I added a second computer, the second computer
> is extremely slow finding one or two URLs, then it fails to
> find any further URLs.
> http://abcnews.go.com/ takes almost a minute
> http://www.google.com/ is not found at all
> ping google.com returns unknown host
>
> My son thinks the Linux box cannot find the DNS server.
> Is that possible? What commands can I enter from a terminal
> to determine such things?

I take it then that you have assigned the ip addresses manually. If it
were DHCP then the router would have given out the information that is
needed about the DNS Servers.

> Does anybody know of an on-line set of step-by-step instructions
> for setting up RedHat/Fedora ethernet?

On-line Step-By-Step no, but you can setup the the network card by opening
a term and typing in

system-config-network

This will give you a gui box to configure your network card.

> Since the WindowsXP connects to the internet OK, I would guess
> that the modem and router are OK, and my problem is within the
> Linux box.

I would agree with you on this one.


--

Regards
Robert

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