Re: pppd is up, but cannot ping/traceroute/connect to internet - help please

From: Clifford Kite (kite_at_see.signature.id)
Date: 07/04/03 

Date: Fri, 4 Jul 2003 08:25:02 -0500

Federico Hanssen <federico_hanssen@hotmail.com> wrote:
> Clifford,
> Thanks for replying. I have used the pppd option a0000 but it didn't
> work. (The ppplog is below). On the other hand the problem started at

Okay.

> the same time with the two ISPs that I have tested, so I think itīs
> very hard it is due to a change in my primary ISP.

Guess I missed that. Well, looking back, I misinterperted a sentence.

So the problem almost certainly lies on your end. The machine has a
darkside (Windows) and the connection works there so I assume the same
modem is used for both sides. The PPP link negotiation messages,
including the timestamps, look good and routing also looks good.
You cannot ping by IP address, even the peer's (ISP connection host's)
IP address, for either ISP which reduces considerably the probability
that pings are blocked at the ISP and eliminates the possibility of a
nameserver problem.

There was no problem for six months and then one day it suddenly
appeared. Can you recall any changes that you made just before the
problem began that might be possibly be related to the problem?

A question that Bill Unruh has asked, and for which I cannot find an
answer from you, is "Do you have a firewall?" A broken firewall could
very well cause the problem.

Also, does this modem require a software driver? But since the setup was
working one day and not the next, I don't know how even a software modem
could cause the problem unless you updated the driver or the kernel.

You are using "Unix98" type device files, something I'm not familiar with,
but that shouldn't matter.

You might try "tcpdump -i ppp0" to see if that shows outgoing ping
requests and incoming ping replies, using the IP address for the
connection host. I don't know if knowing that will help much but
there's really not much left to try.

> I have an ethernet card in my box but it is no connected to any lan.
> Is is possible that I could have messed up anything by using drakconf
> and now the Internet connection is trying to use an alternate method
> of connection that my modem? Is there any file to check that?(my
> distribution is Mandrake 9.0)

It's possible. But there was a default route through the PPP interface,
so it doesn't seem likely that a default route through the NIC would
be causing the problem. In fact if there was an existing NIC default
route at the time of the PPP connection then pppd wouldn't assign a PPP
default route, the PPP default route would have to be assigned by kppp,
a frontend to pppd. I don't know much about any pppd frontend.

A conflict between the NIC IRQ and the serial device IRQ might cause
a problem although this one doesn't "feel" like an IRQ problem to me.
You can see the IRQ assignments with "cat /proc/interrupts."

-- Clifford Kite Email: "echo xvgr_yvahk-ccc@ri1.arg|rot13"
PPP-Q&A links, downloads: http://ckite.no-ip.net/
/* Slogan appropriate for a certain well-known software company:
   FAILURE IS NOT AN OPTION - it is built into the operating system
   and comes bundled with the software. */

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