Network Problem : Can't access beyond router

Whiskerz · 07-23-2006, 06:50 PM

Ok I don't really have any clue what happened. I use Suse 10.0 on an IBM laptop and was away over the week-end taking my laptop with me. I had network access where I was and everything worked just fine. Even installed a kernel patch via auto update. Now I come back home and suddenly no internet.

Some more information : I use a router with dhcp, I get the ip address I am supposed to get, the DNS servers are set correctly and the gateway is set to my router. I can ping my router. But I can't ping any other pc on the network, nor can I ping outside the network. When I run a Knoppix Live DVD everything works just fine, internet, ping inside the network, everything. But somehow it seems that kernel patch wrecked my Suse distribution.

Well at least it would seem this way if I there wasn't this slight deja vu feeling, I had the exact problem before but it miraculously solved itselv after a reboot. Not now though.

Comparing the Knoppix route table and the Suse route table I do see quite some differences and get the feeling, that Suse messed up its routing, but I am no expert in that area.

Anyone have any idea? Its kinda irritating using an operating system which manages to mess up its network either with a security kernel update or with simply connecting to another network ...

Regards

/Whizz

Matir · 07-23-2006, 07:04 PM

Posting the suse routing table would be helpful. Please use 'route -n' to get a numeric version for the most detail.

Whiskerz · 07-24-2006, 02:28 AM

Thanks for trying to help, here is the routing table :

Code:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref   Use Iface
192.168.123.254 0.0.0.0         255.255.255.255 UH    0      0     0   eth0
192.168.178.0   0.0.0.0         255.255.255.0   U     0      0     0   eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0     0   eth0
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0     0   lo
0.0.0.0         192.168.123.254 0.0.0.0         UG    0      0     0   eth0

I have no idea why I have entries for 192.168.178.0 and 169.254.0.0, when I tried to remove them from the table I get a "SIOCDELRT : no such process" message and it will still display in the routing table. I can delete the first entry, which doesn't change anything in the behaviour and which reappears after a reboot.

Just for reference, here is the routing table from the Knoppix Live distribution which works just fine :

Code:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref   Use Iface
192.168.123.0   0.0.0.0         255.255.255.255 U     0      0     0   eth0
0.0.0.0         192.168.123.254 0.0.0.0         UG    0      0     0   eth0

I'd really like to try to get my Suse routing table to look like my Knoppix routing table, to check if that might indeed fix the problem. However I don't seem to be able to do so (as I said I can't delete some entries and after a restart the old routing table is restored), so maybe if anyone could tell me how I purge and refill my routing table in a way which will definitely work and which will not be undone after a restart, that could be a first starting point. Note however that I do use dhcp, and I do use my notebook in other networks from time to time, so a static routing table would not be a very viable solution ... it just seems that Suse configures the table ... hm lets say differently ... and if that could be corrected it would be great.

Regards

/Whizz

Whiskerz · 07-24-2006, 03:53 AM

Update ::

I tried giving the computer a static IP and it worked. The routing table now looks like this :

Code:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref   Use Iface
192.168.123.0   0.0.0.0         255.255.255.255 U     0      0     0   eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0     0   eth0
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0     0   lo
0.0.0.0         192.168.123.254 0.0.0.0         UG    0      0     0   eth0

However I would really like to use dhcp

as I said I do tend to work in different networks, and configuring by hand every time is quite a hassle. Also I'd be interested in knowing what the 169.254.0.0 entry does in my table, don't remember ever using that ip space and I certainly don't need it now. But "route -del 169.254.0.0" just gives the SIOCDLERT message I posted above.

Anyone know how to get Suse to create a working routing table without unnecessary entries when using dhcp?

Regards

/Whizz

Matir · 07-24-2006, 07:19 AM

I can't think of any reason the 169.254.0.0 rule should be present in your routing table. With dhcp, you should be getting a 192.168.123.0 rule as well. You can add one manually with 'route add -net 192.168.123.0 netmask 255.255.255.0 dev eth0'.

Whiskerz · 07-26-2006, 03:22 AM

With a bit of trying around I was finally able to delete those entries from the routing table, also I added an entry like the one you suggested. But still no go. Do I have to restart some kind of process for the changes to take effect?

Again as soon as I configure DNS, gateway and IP by hand it works, but even with a modified route table looking like the one created when I do it manually, Suse refuses do access the net with its DHCP settings - what else could be set dynamically that could be wrong? The DNS are the same, the IP is the same, the routing table is the same, what am I missing?

Regards

Whizz