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Re: pppoe on two different laptops



On 9 Nov 2004, Alexandru Cabuz wrote:
> Until recently I was using Debian testing on an HP Omnibook XE3. Now I am on a
> Dell D600. One annoying problem is that pppoe does not work anymore.
>
> I am using exactly the same /etc/network/interfaces 
> and /etc/ppp/peers/dsl-provider files. I'll copy them below.
>
> What is strange is that the connection seems to get established, meaning I
> do /etc/init.d/networking force-reload and then ifconfig says ppp0 is 
> configured, and I can see the IP address and the packets are getting 
> through... even my firewall is taking hits. But when I start kmail or 
> mozilla, they do not seem to be able to connect to the network. Mozilla just 
> tries to connect for a couple of minutes and then gives up. Same with
> kmail.

[...]

> What would prevent mozilla and kmail from seeing the connection even though
> ifconfig, says everything is cool?

Packet size issues - PPPoE connections are infamous for silently
discarding oversized packets with no notification and, thus, breaking
PMTU discovery.

This discusses the problem and solutions under Linux:

<http://linux-universe.com/HOWTO/IP-Masquerade-HOWTO/mtu-issues.html#AEN2563>


This is usually visible as small packets working, but large packets
failing.  So, you see connection and can ping things, but your web
request gets a tiny way and then stalls on large packets. :/

        Daniel

-- 
Copyright law is totally out of date. It is a Gutenburg artifact.
Since it is a reactive process, it will probably have to break
down completely before it is corrected.
        -- Nicholas Negroponte, _Being Digital_, 1995



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