Why sometimes my ubuntu server cannot connect to modem?

shihao · 08-21-2009, 04:43 AM

Hi, I am facing problem while I try to connect the Ubuntu server to modem.

I am using few command like pppoeconf, pon dsl-provider, poff, plog, ifconfig to check, dial, discoonect the connection.

I still dunno why sometimes I able to ping www.google.com and sometimes cannot..

Please help.. Thanks.

repo · 08-21-2009, 06:22 AM

Take a look in the logfiles, when you make the connection, and when you have problems to connect
/var/log/*

shihao · 08-23-2009, 09:13 PM

Hi, thanks for the reply. There are many files inside the var/log, I wonder which one I should view.

Generally, my step is
1) configure using pppoeconf
2) use 'pon dsl-provider' command
3) ping www.google.com (Sometimes works sometimes does not)

I am still new at linux, need a precise guide. Please Advice. Thank you.

repo · 08-24-2009, 12:55 AM

Open a terminal and login as root
type

Code:

tail -f /var/log/messages

open another terminal and make the connection.
Look at the output in the first terminal.

shihao · 08-24-2009, 01:55 AM

Hi, Thanks for the reply.

-The log file shows:
-connect ppp0 <--> eth0
-Connection Terminated
-Timeout waiting for PADS packets
-ppp session is 6545
-Using Interfaces ppp0
-Connect ppp0 <--> eth0
-Remote messages: More Session Exceeded
-Connection Terminated
-Timeout waiting for PADO packets
-ppp session us 6570
-Timeout for PADO packets
-MARKS
-MARKS

repo · 08-24-2009, 02:06 AM

Seems to me there is a problem with the provider.

Quote:

-Timeout waiting for PADO packets

Once the user's computer has sent the PADI packet, the DSL-AC replies with a PADO packet,

Perhaps you can contact the provider, or try to reconnect again until you get the response from the DSLAM, which needs to sign you in and provide the ip address, gateway, dns.....

So the problem is that the connection with the provider is not established, not that ubuntu can't communicate with the modem.

shihao · 08-24-2009, 03:55 AM

Dear Repo,

You means I have to constantly use command 'pon dsl-provider' until the connection established?

repo · 08-24-2009, 05:44 AM

AFAIK you can set in pppoeconf to reconnect if the connection failes

Quote:

RETRY_ON_FAILURE=yes

You only need to use

Code:

adsl-start

In order to start the connection.
Use the tail option to see what happens

shihao · 08-25-2009, 06:37 AM

Dear Repo,

Unfortunately, the pppeoconf command doesn't show 'RETRY_ON_FAILURE' Option to me.

Moreover, 'adsl-start' return 'command not found'

I have search from some forum they said that '-Timeout waiting for PADO packets' error usually is something related to cable connection. I have double check already. Seems doesn't works also.

Looking for advice.

Thanks

repo · 08-25-2009, 06:52 AM

Quote:

Moreover, 'adsl-start' return 'command not found'

I used this years ago, probably it changed.

Quote:

Timeout waiting for PADO packets' error usually is something related to cable connection.

It means the providers dlam doesn't answer.

Your best option is to retry until you have a connection.
Perhaps you can contact the provider.
They can verify what happens when you try to connect.

Another option is to buy a router :-)