Network is unreachable.

[svennam]

Hi ...
Help please.
I have installed Ubuntu Server 8.10 on a new desktop. Then I installed desktop environment into that server to download oracle Express Edition Database Software to install it. My problem is the Firefox worked a couple of days well. Suddenly it started not working showing Network is in reachable. I opened Terminal window and typed as follows:

ping 91.189.94.249
I got network is unreachable.
The fact is I have wired network,which is working yesterday.
Then I typed ping 127.0.0.1
Then it is transmitting packets and received packets.
Then I typed ifconfig eth0
I got eth0: error fetching interface information: Device not found.
If ping anything other than 127.0.0.1, I am getting network is unreachable.
Don't have more ideas. Need help.

[daboroe]

Hi ...
Help please.
I have installed Ubuntu Server 8.10 on a new desktop. Then I installed desktop environment into that server to download oracle Express Edition Database Software to install it. My problem is the Firefox worked a couple of days well. Suddenly it started not working showing Network is in reachable. I opened Terminal window and typed as follows:

ping 91.189.94.249
I got network is unreachable.
The fact is I have wired network,which is working yesterday.




Then I typed ping 127.0.0.1
Then it is transmitting packets and received packets.
Then I typed ifconfig eth0
I got eth0: error fetching interface information: Device not found.
If ping anything other than 127.0.0.1, I am getting network is unreachable.
Don't have more ideas. Need help.
Pinging 127.0.0.1 is back and forth to your network card. I would tried to reseed it on the motherboard. It sounds like it is detecting it and not at the same time. If it was not in right then you would not be able to ping 127.0.0.1.

this is very interesting.

try to run this command see what happens:


#Sudo ifup eht0

[netztier]

Pinging 127.0.0.1 is back and forth to your network card.

Sorry, that's wrong.

Packets to/from 127.0.0.1 should never even get close to any network card - you can even have such a loopback interface without even having a physical network card in your system. It's completely "virtual".

regards

Marc

[netztier]

Then I installed desktop environment into that server


Great! :-/ Now /etc/network/interfaces and NetworkManager are possibly in conflict about who manages which network interface card. Again a reason why I personally never suggest to run the ubuntu-desktop package on a server.

If you absolutely need a GUI, install Ubuntu Desktop; you can always add a server or custom kernel with it's special optimisations later on, if you need them.



ping 91.189.94.249
I got network is unreachable.


We need the outputs of these commands (working from upper to lower layers in the ISO/OSI network layer model):

to see which DNS servers are configured: cat /etc/resolv.conf
to see if there's manually configured interfaces: cat /etc/network/interfaces
to see the local routing table: netstat -nr
to see the state of the interfaces: ifconfig -a
to see if and what ethernet IFs were seen during startup: dmesg | grep eth


regards

Marc

[svennam]

Thanks Marc. I will execute commands you suggested and post the output when I get back home.

[Iowan]

Sorry, that's wrong.
Packets to/from 127.0.0.1 should never even get close to any network card I, too, thought pinging 127.0.0.1 checked whether network card was functional...
Won't be the last time I'm wrong...

[mlinux]

127.0.0.1 just a virtual network loop back, no network card require.

As what netztier recommend, server should not have the desktop GUI. Yes, is tough for window user to navigate the server using command line. If you must have the GUI, can consider remote access via webmin but now you have to resolve the network problem first before remote access.

[svennam]

Great! :-/ Now /etc/network/interfaces and NetworkManager are possibly in conflict about who manages which network interface card. Again a reason why I personally never suggest to run the ubuntu-desktop package on a server.

If you absolutely need a GUI, install Ubuntu Desktop; you can always add a server or custom kernel with it's special optimisations later on, if you need them.



We need the outputs of these commands (working from upper to lower layers in the ISO/OSI network layer model):

to see which DNS servers are configured: cat /etc/resolv.conf
to see if there's manually configured interfaces: cat /etc/network/interfaces
to see the local routing table: netstat -nr
to see the state of the interfaces: ifconfig -a
to see if and what ethernet IFs were seen during startup: dmesg | grep eth


regards

Marc


Here are the outputs for the commands you suggested:


cat /etc/resolv.conf:
domain Belkin
search Belkin
nameserver 192.168.2.1

cat /etc/network/interfaces:
#The file describes the network interfaces available on your system
#and how to activate them. For more information, see interfaces(5)
#The loopback network interface
auto lo
iface lo inet loopback
#The primay network interface
auto eth0
iface eth0 inet dhcp

netstat -nr:
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface

ifconfig -a
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope: Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:20550 errors:0 dropped:0 overruns:0 frame:0
TX packets:20550 errors:0 dropped:0 overruns:0 carrier:0
collision:0 txqueuelen:0
pan0 Link encap:Ethernet HWaddr 96:49:56:2e:c6:63
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0(0.0 B) TX bytes:0(0.0 B)

dmesg | grep eth:
[ 3.126692] Driver 'sr' needs updating - please use bus_type methods
[ 3.129345] Driver 'sd' needs updating - please use bus_type methods

[aesis05401]

The please use bus type methods messages are supposedly just noise. I have seen that conversation done to death on Launchpad and lkml - and the resolution is always that those messages are not related to the issues.

Here is one example: https://bugs.launchpad.net/ubuntu/+bug/186167

That thread has a link to a lkml conversation, and I have seen others including one where a kernel hacker explained where those messages are coming from and why they don't matter.

[mlinux]

Your eth0 is gone? Not listed with the ifconfig -a. Hardware problem? May be should force fix ip address to the

/etc/network/interfaces

[netztier]

cat /etc/resolv.conf:
domain Belkin
search Belkin
nameserver 192.168.2.1



Suggestion: use
[/CODE ] tags around text snippets from console commands and console output. The text becomes a lot easier to read. Now. That's interesting. Assuming you have no eth0 nor a wlan0 interface - these informations must be a leftover from the time when DHCP was still working.


[CODE]cat /etc/network/interfaces:
#The file describes the network interfaces available on your system
#and how to activate them. For more information, see interfaces(5)
#The loopback network interface
auto lo
iface lo inet loopback
#The primay network interface
auto eth0
iface eth0 inet dhcp


Hm. So we have a DHCP configuration for eth0 - still, we don't know if the kernel has actually seen an ethernet interface and if it had named it "eth0".




netstat -nr:
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface


Empty routing table, not even a local subnet route - ok, that's to be expected when there is no active LAN interface.




ifconfig -a
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope: Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:20550 errors:0 dropped:0 overruns:0 frame:0
TX packets:20550 errors:0 dropped:0 overruns:0 carrier:0
collision:0 txqueuelen:0
pan0 Link encap:Ethernet HWaddr 96:49:56:2e:c6:63
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0(0.0 B) TX bytes:0(0.0 B)


Allright then, the kernel has not seen any other interfaces than lo (Loopback).




dmesg | grep eth:
[ 3.126692] Driver 'sr' needs updating - please use bus_type methods
[ 3.129345] Driver 'sd' needs updating - please use bus_type methods

Commonly, the kernel writes out someting to dmesg that contains the string "eth" if it discovers and activates an ethernet interface.

Hm.

Now we need to dig deeper. It might be a lot of text output, so I suggest to copy&paste it into a text file and usb-stick-copy it over to a working computer and add it as a file attachment to your posting.

To find out what NIC is in your computer and to see how it is seen by the kernel, can you please show us the outputs of these commands?


lspci
sudo lshw -c network
cat /etc/udev/rules.d/70-persistent-net.rules
lsmod




regards

Marc

[netztier]

That thread has a link to a lkml conversation, and I have seen others including one where a kernel hacker explained where those messages are coming from and why they don't matter.

Agreed, these messages that showed up from dmesg are irrelevant to this thread.

I was hoping to see some substrings eth from "ethernet" or "eth0" or "eth1", hence I asked the OP to grep dmesg's output for "eth".

regards

Marc

[svennam]

I will try. The problem is, I have to write the output from each command on paper and use another computer, type and post. I will see whether I can do it.

[svennam]

I could do it easily following your suggestions. The following is the output for each of the commands:

lspci:
00:00.0 Host bridge: Intel Corporation 4 Series Chipset DRAM Controller (rev 03)
00:02.0 VGA compatible controller: Intel Corporation 4 Series Chipset Integrated Graphics Controller (rev 03)
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01)
00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 01)
00:1c.1 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 2 (rev 01)
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #1 (rev 01)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #2 (rev 01)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #3 (rev 01)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #4 (rev 01)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 01)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev e1)
00:1f.0 ISA bridge: Intel Corporation 82801GB/GR (ICH7 Family) LPC Interface Bridge (rev 01)
00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family) SATA IDE Controller (rev 01)
00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 01)

sudo lshw -c network:
*-network DISABLED
description: Ethernet interface
physical id: 1
logical name: pan0
serial: 96:ba:f4:5b:a3:41
capabilities: ethernet physical
configuration: broadcast=yes driver=bridge driverversion=2.3 firmware=N/A link=yes multicast=yes

cat /etc/udev/rules.d/70-persistent-net.rules:
# This file was automatically generated by the /lib/udev/write_net_rules
# program run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single line.

# PCI device 0x10ec:0x8168 (r8169)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:24:1d:24:d6:c6", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

lsmod:
Module Size Used by
binfmt_misc 16904 1
rfcomm 44432 0
sco 18308 2
bridge 56980 0
stp 10628 1 bridge
bnep 20480 2
l2cap 30464 6 rfcomm,bnep
bluetooth 61924 6 rfcomm,sco,bnep,l2cap
ipv6 263460 24
ppdev 15620 0
acpi_cpufreq 15500 0
cpufreq_userspace 11396 0
cpufreq_stats 13188 0
cpufreq_ondemand 14988 2
freq_table 12672 3 acpi_cpufreq,cpufreq_stats,cpufreq_ondemand
cpufreq_powersave 9856 0
cpufreq_conservative 14600 0
wmi 14504 0
container 11520 0
sbs 19464 0
pci_slot 12552 0
video 25104 0
output 11008 1 video
sbshc 13440 1 sbs
battery 18436 0
af_packet 25600 0
iptable_filter 10752 0
ip_tables 19600 1 iptable_filter
x_tables 22916 1 ip_tables
ac 12292 0
lp 17156 0
loop 23180 0
pcspkr 10624 0
psmouse 45200 0
serio_raw 13444 0
evdev 17696 7
parport_pc 39460 1
parport 42604 3 ppdev,lp,parport_pc
snd_hda_intel 381360 1
snd_pcm_oss 46720 0
snd_mixer_oss 22784 1 snd_pcm_oss
snd_pcm 83332 2 snd_hda_intel,snd_pcm_oss
snd_seq_dummy 10884 0
snd_seq_oss 38400 0
iTCO_wdt 18596 0
iTCO_vendor_support 11652 1 iTCO_wdt
snd_seq_midi 14336 0
snd_rawmidi 29696 1 snd_seq_midi
snd_seq_midi_event 15232 2 snd_seq_oss,snd_seq_midi
snd_seq 57776 6 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_seq_mid i_event
snd_timer 29832 2 snd_pcm,snd_seq
snd_seq_device 15116 5 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_rawmidi ,snd_seq
button 14224 0
snd 63268 11 snd_hda_intel,snd_pcm_oss,snd_mixer_oss,snd_pcm,sn d_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_seq_de vice
shpchp 38036 0
pci_hotplug 35236 1 shpchp
soundcore 15328 1 snd
snd_page_alloc 16264 2 snd_hda_intel,snd_pcm
ext3 132872 4
jbd 55444 1 ext3
mbcache 16004 1 ext3
usbhid 35968 0
hid 50560 1 usbhid
sd_mod 42264 6
crc_t10dif 9984 1 sd_mod
sr_mod 22212 0
cdrom 43040 1 sr_mod
sg 39220 0
pata_acpi 12160 0
ata_piix 24708 5
ata_generic 12804 0
libata 176032 3 pata_acpi,ata_piix,ata_generic
scsi_mod 155212 4 sd_mod,sr_mod,sg,libata
dock 16656 1 libata
ehci_hcd 43916 0
uhci_hcd 30864 0
usbcore 149360 4 usbhid,ehci_hcd,uhci_hcd
thermal 23708 0
processor 42284 4 acpi_cpufreq,thermal
fan 12420 0
fbcon 47392 0
tileblit 10752 1 fbcon
font 16512 1 fbcon
bitblit 13824 1 fbcon
softcursor 9984 1 bitblit
fuse 60700 3

[netztier]

a suggestion: when you copy&paste commands or output from the command line, enclose it in CODE tags by highlighting the text with the mouse and klicking the # button in the toolbar above the edit box. It makes reading a lot easier, because you can instantly tell apart what is text and what ist - well... "code".





lspci:
00:00.0 Host bridge: Intel Corporation 4 Series Chipset DRAM Controller (rev 03)
00:02.0 VGA compatible controller: Intel Corporation 4 Series Chipset Integrated Graphics Controller (rev 03)
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01)
00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 01)
00:1c.1 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 2 (rev 01)
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #1 (rev 01)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #2 (rev 01)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #3 (rev 01)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #4 (rev 01)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 01)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev e1)
00:1f.0 ISA bridge: Intel Corporation 82801GB/GR (ICH7 Family) LPC Interface Bridge (rev 01)
00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family) SATA IDE Controller (rev 01)
00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 01)


That's not good. There's no ethernet controller in there!



sudo lshw -c network:
*-network DISABLED
description: Ethernet interface
physical id: 1
logical name: pan0
serial: 96:ba:f4:5b:a3:41
capabilities: ethernet physical
configuration: broadcast=yes driver=bridge driverversion=2.3 firmware=N/A link=yes multicast=yes


Hm. "pan0" makes me think of firewire or bluetooth, but not ethernet. I have a similarly looking pan0 on my PC here - it certainly does not refer to a real ethernet interface.





cat /etc/udev/rules.d/70-persistent-net.rules:
# This file was automatically generated by the /lib/udev/write_net_rules
# program run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single line.

# PCI device 0x10ec:0x8168 (r8169)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:24:1d:24:d6:c6", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"


That must be a leftover from when the NIC was still working. I would suspect that this NIC has somehow "disappeared" from the PCI bus.




lsmod:
Module Size Used by
binfmt_misc 16904 1
rfcomm 44432 0
sco 18308 2
bridge 56980 0
...
...
...
bitblit 13824 1 fbcon
softcursor 9984 1 bitblit
fuse 60700 3


Hm. Now it's expected that no module for the r8169-based NIC appears in this list, since we're the PCI device is missing in the first place.

Can you get into the BIOS of that computer to see if the (onboard?) ethernet interface is disabled? Now why and how that could happen, I have no clue at all...

regards

Marc

[svennam]

I can see that. What should I do, If it is disabled?
By the way I am new to this form. I did not understand your following suggestion. Can you explain more on this
"a suggestion: when you copy&paste commands or output from the command line, enclose it in CODE tags by highlighting the text with the mouse and klicking the # button in the toolbar above the edit box. It makes reading a lot easier, because you can instantly tell apart what is text and what ist - well... "code"."
I don't see # button in toolbar. I don't see CODE tag, but I see Wrap [Code] tags.

[koenn]

I don't see # button in toolbar. I don't see CODE tag, but I see Wrap [Code] tags.

yes, it's that one;
like so:


________________
< that's the one >
----------------
\ ^__^
\ (oo)\_______
(__)\ )\/\
||----w |
|| ||

[svennam]

What happens if I use quote. Just testing..
I am just testing what happens if I use

[netztier]

I can see that. What should I do, If it is disabled?


Well - what about enabling it? Then reboot and look at the output of lspci first, if it lists an "Ethernet conroller". On my system with Intel NICs, these look like this in lspci:


01:08.0 Ethernet controller: Intel Corporation 82541PI Gigabit Ethernet Controller (rev 05)
05:00.0 Ethernet controller: Intel Corporation 82572EI Gigabit Ethernet Controller (Copper) (rev 06)


Guessing from the leftovers we saw in /etc/udev/rules.d/70-persistent-net.rules on your system, I would expect the name "Realtek" to show up in there somewhere.

If the onboard Ethernet NIC is activated in BIOS but does not show up in lspci, something's seriously wrong. In that case, I suggest to disable it in the BIOS and installing a PCI or PCIe-NIC instead.

regards

Marc

[svennam]

Marc,
I appollogise my delay. I have entered into bios. But I could not find (onboard?) ethernet interface. But I found the following:
On board H/W Lan Enabled
On board LAN Boot ROM Disable
On board Serial Port 1 [3F8/IRQ 4]
On board Serial Port 2 [2F8/IRQ 3]
On board parallel Port [378/IRQ 7]

When I entered Bios I found the following options. I appreciate If you could tell me which option should I select to see what you wnated.

MB Intelligent Tweaker
Standard CMOS feature
Advanced BIOS feature
Integrated peripherils
Power Management set up
PnP/PCI configurations
PC Health status
Load Fail-defaults
Load Optimized defaults
Set Supervisor Password
Set User password etc., etc.

[mlinux]

On board H/W Lan Enabled


This indicate that your onboad network is enabled. Next is to look at the network cable connector at the server, when is up and running, you should see 2 LED light next to the socket. If not, the network card may be at fault.

Quick fix would be disable the on board lan and install a PCI NIC.

[svennam]

Hi mlinux,
I don't know where is on board lan. Then how to install PCI NIC. Little more explanation would held me.

[mlinux]

Hi mlinux,
I don't know where is on board lan. Then how to install PCI NIC. Little more explanation would held me.

You can not see the on boad lan but the network socket normally at the back above the USB connector. The place you plug in your RJ45 network cable.

Before you proceed, may be you should get a copy of the linux that run on CD only. If you can access internet from the CD verion, your on board network is working. We can then diagnose from there.