Networking crisis :o)

[dimitriv]

Hi

I just upgraded from 8.1 to latest production build and my DSL network connection is failing to connect - and I can't connect to the internet (the crisis ;)). I have tested the modem & ISP connection, they are fine.

Looking in the syslog after failed attempt to connect it shows NetworkManager reporting

<WARN> pppd_timed_out(): Looks like pppd didn't initialize our dbus module

&

Marking connection 'ISP1' invalid

Under the ISP1 connection settings, I have tried All and one at a time of the PPP Settings 'Configure Methods'

Please advise any steps to fix or troubleshoot.

Many thanks

[dimitriv]

BUMP

Please any ideas, internet is required for 90% of my Ubuntu use...
thank you

[dineshs]

Do you have a DSL modem/router connected via ethernet?What is the result of

ifconfig

[dineshs]

Also post the output of
cat /etc/resolv.conf

[dimitriv]

Hi

Yes the modem is attached via ethernet.

ifconfig gives the following

eth0 Link encap:Ethernet HWaddr 00:23:54:d5:fb:e0
inet6 addr: fe80::223:54ff:fed5:fbe0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:9 errors:0 dropped:0 overruns:0 frame:0
TX packets:17 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:545 (545.0 B) TX bytes:2324 (2.3 KB)
Interrupt:31

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:4 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:240 (240.0 B) TX bytes:240 (240.0 B)


& the other request generated this

# Generated by NetworkManager


However, since i've been pretty keen to find a resolution I tried these steps although i'm not sure if that was the right thing to do? If not please advise and i'll undo each of step
http://www.ubuntugeek.com/how-to-setup-networkmanager-work-with-pppoe-connection-on-ubuntu-9-10-karmic.html

Thank you

[dineshs]

You need to modify the following files.In a terminal type

gksudo gedit /etc/resolv.conf
Modify the file like this(copy and paste)

# Generated by NetworkManager
nameserver 8.8.8.8
nameserver 8.8.4.4
Similarly

gksudo gedit /etc/network/interfaces
The file should contain only this

auto lo
iface lo inet loopback
comment out (ie put a # in front of) all other lines
Now
Right-click on the nm-applet and then click on Edit Connections.
Select the tab DSL and click add
give username ,password service name(something) and check connect automatically then apply
ref
https://help.ubuntu.com/community/NetworkManager0.7

[dimitriv]

dineshs, thank you very much for helping to get this working. I tried adding the google nameservers as you described but this hasn't fixed it. The second step wasn't necessary as the file was already as you suggested.

I don't have a Service name, what should I enter? I tried (something) and various others.

On the Wired tab the MAC address is blank
The modem plugs in to the PC ethernet. I've put in the eth0 mac but it still doesn't work.

Please advise next thing to try

Thanks

[dimitriv]

Hi, I urgently need to get this working - any ideas please?
Thank you.

[tgalati4]

Sounds like the routing tables in the dsl modem or router are messed up. Try rebooting the DSL modem first (unplug any routers as well).

Once the DSL modem is up and running, then replug any routers as well. Wait for them to reboot completely.

Then from a terminal, post the output of:

netstat -r

ping www.google.com (control-C to quit)

[dimitriv]

Hi

$ netstat -r
Destination Gateway Genmask Flags MSS Window iritt Iface

[no other data]

ping www.google.com
ping: unknown host www.google.com

What's next, this machine must have internet...

thank you for your assistance

[dineshs]

Try to assign an IP manually to your ethernet interface.For this,follow the same guide
https://help.ubuntu.com/community/NetworkManager0.7
ie
Right-click on the nm-applet and then click on Edit Connections.
Select the tab, wired
select the connection and click edit(you can add the ethernet connection if not listed)
select ipv4
method-manual
click add
give IP address,mask and gateway(Hope you know that)
then hit enter
DNS 8.8.8.8
then click apply
Now try to ping your modem IP

[dimitriv]

hi

thanks for the suggestion. The modem is auto configured, it connects itself grabbing an IP from dhcp. How can i tell what IP address has been assigned? Also since it uses DHCP this IP address will change, so entering a static will hit problems. I have another modem & pc from which i can grab the mask and gateway info as they'll [probably] be the same.

Thank you

[tgalati4]

Your routing table is messed up (and non existent).

It should look like:

tgalati4@tpad-Gloria7 ~ $ netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
link-local * 255.255.255.0 U 0 0 0 eth1
169.254.0.0 * 255.255.0.0 U 0 0 0 eth1
default 192.168.1.1 0.0.0.0 UG 0 0 0 eth1

-------------

The last line is critical, it shows that your default gateway is the IP address of your router or modem. If that line doesn't exist, then linux doesn't know how to get out to the internet.

Normally this is conveyed automatically from your DSL modem to your computer automatically.

Your ifconfig is showing an ipv6 address and your DSL modem is probably ipv4. Make sure ipv6 is turned off:

cat /etc/modprobe.d/blacklist.conf

Add the line:

# blacklist ipv6
blacklist ipv6

sudo nano /etc/modprobe.d/blacklist.conf

reboot (One of the few times where your really do need to reboot in linux.)

This is for Jaunty. It may have changed for Lucid.

[dineshs]

hi
How can i tell what IP address has been assigned?

ifconfig
will tell that

Also since it uses DHCP this IP address will change, so entering a static will hit problems.
If you are assigning an IP outside the range of the DHCP server in the router , it will not
Once you get def gateway as tgalati4 suggested,you can access your router to check what is the DHCP range set in it
I think you are now connected to internet since DHCP has done its duty

[dimitriv]

thanks for the suggestions

How do I create that routing table? I've tried to identify a file that needs editing or the command to insert that - please clarify.

much appreciated

[dineshs]

pl post the output of
netstat -rand
ifconfig

[dimitriv]

As requested:

~$ netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface

~$ ifconfig
eth0 Link encap:Ethernet HWaddr 00:23:54:d5:fb:e0
inet6 addr: fe80::223:54ff:fed5:fbe0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:19 errors:0 dropped:0 overruns:0 frame:0
TX packets:19 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1145 (1.1 KB) TX bytes:2734 (2.7 KB)
Interrupt:31

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:4 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:240 (240.0 B) TX bytes:240 (240.0 B)

Thank you

[tgalati4]

Your ifconfig should look something like:

eth1 Link encap:Ethernet HWaddr 00:13:ce:89:ec:79
inet addr:192.168.1.154 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::213:ceff:fe89:ec79/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:7175 errors:2 dropped:2 overruns:0 frame:0
TX packets:4538 errors:0 dropped:5 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3024041586 (3.0 GB) TX bytes:257797146 (257.7 MB)
Interrupt:21 Base address:0xa000 Memory:b4001000-b4001fff

----------------

You are missing the inet (ipv4) address line. Why, well you might be in ipv6 mode:

Post the output of

ps -ef | grep ipv6

and

lsmod | grep ipv6

If you get output from the above, then that means your computer is in ipv6 mode and your router probably only speaks ipv4 mode. Try blacklisting ipv6.

[dimitriv]

thanks for the reply, which method do i use to disable ipv6?

I followed the instructions here
http://en.kioskea.net/faq/759-ubuntu-disabling-ipv6-support

For the instructions for 9.1, this line did not exist
GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash”
i tried manually entering this with the disable flag but but the output of
ps -ef | grep ipv6

continues to show ipv6

*(the output below)
jon 2536 2466 0 20:03 pts/0 00:00:00 grep ipv6

I also tried editing the file /etc/modprobe.d/blacklist
the file was blank initially, I entered the line specified
but after both of these changes the output was as above*

is there another method or solution?

thanks

[callmebeibei]

BUMP, BUMP,

Ping www.google.com:guitar: (http://www.google.com:guitar:)

[tgalati4]

If lsmod doesn't show ipv6 then it's not loaded. Could be a network card problem or cable problem. Reseat your cables. Check for rat bites.

[dimitriv]

Hi

Thanks for all your support with this, we must get this fixed this weekend

Here’s a summary of the problem and actions taken:
• Ubuntu upgraded from 8.1-9.1 all successful, except internet access broken
• PPPOE Modem is attached and lights indicate connected to ISP, connection problem exists between PC to Modem


The resolv.conf was modified to include nameservers as below
gksudo gedit /etc/resolv.conf

# Generated by NetworkManager
nameserver 8.8.8.8
nameserver 8.8.4.4

Interfaces was checked satisfactorily for the setting below
gksudo gedit /etc/network/interfaces

auto lo
iface lo inet loopback

Netstat & ping generate as below
~$ netstat -r
Destination Gateway Genmask Flags MSS Window iritt Iface

[no other data]

ping www.google.com
ping: unknown host www.google.com

I tried one other step – is this doing harm, should I reverse this out?
However, since i've been pretty keen to find a resolution I tried these steps although i'm not sure if that was the right thing to do? If not please advise and i'll undo each of step
http://www.ubuntugeek.com/how-to-set...10-karmic.html


Manual IP
I’ve tried manually editing the connection and entering an IP (should be DHCP, don’t know what that DHCP address is) and copied subnet mask and gateway settings from my other pc/modem connected to same isp.


Routing table
tgalati4, suggested my routing table is messed up (and non existent).

It should look like:

tgalati4@tpad-Gloria7 ~ $ netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
link-local * 255.255.255.0 U 0 0 0 eth1
169.254.0.0 * 255.255.0.0 U 0 0 0 eth1
default 192.168.1.1 0.0.0.0 UG 0 0 0 eth1

How do I create that routing table?

Blacklist
cat /etc/modprobe.d/blacklist.conf

Add the line:

# blacklist ipv6
blacklist ipv6

sudo nano /etc/modprobe.d/blacklist.conf


Disabling IPV6

I followed the instructions here
http://en.kioskea.net/faq/759-ubuntu...g-ipv6-support

For the instructions for 9.1, this line did not exist
GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash”
i tried manually entering this with the disable flag but but the output of
ps -ef | grep ipv6

continues to show ipv6

*(the output below)
jon 2536 2466 0 20:03 pts/0 00:00:00 grep ipv6

I also tried editing the file /etc/modprobe.d/blacklist
the file was blank initially, I entered the line specified
but after both of these changes the output was as above*

what's the correct method to disable ipv6 on 9.1?

Outputs from
~$ netstat -r

~$ ifconfig

are in previous post #17

Ping results are still ‘unknown host’

Modem Cable
The modem cable is correctly inserted, there are no rat bites or damage etc.

Please provide any additional ideas based on the above, or new suggestions

Thank you in advance

[tgalati4]

You have ipv6 disabled. The entry that you see is your grep search on "ipv6" so that's normal.

You can manually add a routing table:

man route

sudo route add default gw 192.168.1.1

netstat -r

ping www.google.com

Your IP address for your gateway may be different (such as 192.168.0.1, or some other address).

[dimitriv]

hi tgalati4

when i tried entering an add route, or running a copy of the command you gave in your last post I get
SIOCADDRT: No such process

I've search the forum and haven't found a suitable resolution yet.
I've just got these 3 lines to add routes for completing this

link-local * 255.255.255.0 U 0 0 0 eth0
169.254.0.0 * 255.255.0.0 U 0 0 0 eth0
default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0

thank you

[tgalati4]

Try to boot from a live cd using an older version of ubuntu. See if your network comes up.