[ILUG] NewBee with suse again.

[Chris Higgins]

On Mon, 11 Oct 2004 19:07:55 +0100
"Fred" <Woodfrederick at hotmail.com> wrote:

> Hi,
> Still haveing trouble setting up a connection with my suse linux
> instalation. My connection (1Meg home breez from Irish BB) works fine
> under windows.
> 
> The network card is picked up just fine as far as I can see. ( Have
> tried three network cards and only one was definitely not supported)
> The card used now is a nice old one ( just to make sure the drivers
> are available) SMC EZ Card PCI 10 Adapter (SMC1208)
> 
> I can get connected with a live Knoppix CD, and that is nice..... but
> not a live CD of suse 9.1 or the installed 9.0 professional version.
> 
> I get these results from ifconfig after setting up the IP add, Subnet
> Mask, Gateway and DNS settings for the network card with YaST.
> 
> linux:/home/user # ifconfig eth0
> eth0 Link encap:Ethernet HWaddr 00:E0:29:61:21:97
>         inet addr:60.231.60.201 Bcast:60.231.60.255
>         Mask:255.255.255.192 inet6 addr: fe80::2e0:29ff:fe61:2197/64
>         Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
>         RX packets:123 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:20 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 txqueuelen:100
>         RX bytes:7388 (7.2 Kb) TX bytes:1440 (1.4 Kb)
>         Interrupt:3 Base address:0x8000
> 
> When I open the browser and try a URL I get nothing.
> 
> Any help or leads on where to look ..FAQs, help files, R.T.F.Ms. would
> be appreciated. Irish BB in the meantime are not responding.

Ok - you have an IP address, so either 
a/ You hard coded it in
b/ Something on your machine talked to the far end and got allocated it
    ( dhcp client )

Your IP host needs three pieces of IP network information to be able
to successfully connect to a network - IP address, Subnetmask and
default gateway

The IP address and subnetmask are displayed in the output of ifconfig, 
so that's fine - the question is now 
 - do you have a valid default gateway

The command 'netstat -rn' should display your routing table, which should
list all the IP networks your machine is interested in - mine reads 

luggage:~> netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
172.16.1.0      0.0.0.0         255.255.255.0   U         0 0          0 eth0
0.0.0.0         172.16.1.1      0.0.0.0         UG        0 0          0 eth0

The entry you are looking for is the 0.0.0.0 entry, and what you want to
try do is ping the IP address listed.

If you don't have a default gateway, then it would explain why things
don't work - it should have been negotiated with the IP address.

You should be able to ping the IP address listed, and that device should
reply (normally - unless your ISP are blocking the PING packets ) 

Assuming all that works - then you have sucessfully negotiated
an IP address / default gateway - and you are now on the internet.

The next test is 'traceroute -n 16.1.0.4'  ( ip address doesn't really
matter too much ), and you should see traceroute return 
a list of values ... as long as you get something back  ( and not
* * * ) then you are mostly happy.

If you get to here - and everything is working, then you have connectivity
to the world - and the piece of the puzzle missing is DNS... in the
traceroute and netstat commands the argument '-n' says 
"dont do DNS lookups".

To get DNS to work you need valid DNS servers in /etc/resolv.conf,
these should also have been negotiated as part of the IP address
negotiation. Check what's in your /etc/resolv.conf, and for each
of the servers listed - try ping them, and if that succeeds try
dig ns rte.ie @192.111.39.1 ( replacing 192.111.39.1 with the addresses
listed in your resolv.conf

If your resolv.conf doesn't have entries, then create some
using the DNS servers for your ISP.

Assuming all that works, then you should be able to ping
machines by name, and traceroute to places by name.

Once you are there - then any other IP applications should
also be able to connect by name ( so www.rte.ie will
resolv to 217.173.98.160 - or whatever the RTE loadbalancers
decide is the appropriate answer to give )


If at any stage along, the process fails - then you can't continue
until you fix it , as all the subsequent steps rely on the ones that
went before them.

Because your windows setup was working, it seems reasonable
to believe that the servers at the ISP end are properly offering
correct IP address/subnetmask - default gateway and DNS
settings for your account - so there is no reason why the linux
client software shouldn't be getting and using the correct information.

That leaves the possiblity that ( as others have suggested ) the
linux networking software is filtering the packets and throwing
them away. If this is the case then by walking through the steps
above you should be able to find a step that fails, and it is a lot
easier to troubleshoot a specific 'i have an IP address but I
can't ping' problem - rather than a 'it wont work' problem.

It may be something as simple as the wrong default route
because someone put one into a field when instaling the box, 
but the sequence of steps will identify where to look.
 
If you fail to get the ping to work - do as others have suggested,
and disable any firewalling you may have in place and see if that
helps..... once you get online - make sure you implement suitable
firewall rules for your config.

Don't drive without a seatbelt - don't surf without a firewall,
don't drink without a floor to hold onto.

> 
> Thanks
> 
> Fred
> 
> -- 
> Irish Linux Users' Group
> http://www.linux.ie/mailman/listinfo/ilug/
> 


-- 
Chris Higgins                              
Darach Technology Ltd                      tel: +353-1-6204370
email: chris.higgins at darach.ie          fax: +353-1-6204371
http://www.darach.ie