Re: [Pengfork-devel] tcp dump

[Jean-Charles Salzeber]

On Wed, Oct 02, 2002 at 21:12, Ced wrote:
> Hello pengfork-devel,
> 
>   i have done a tcp dump of an attemp of connection with AOL 7.0
>   Connection stops at step 5, cose of capturing packets.
> 
>   I hope it could help you.
> 
>   (done with ethereal 0.9.7)
> 
> -- 
> Best regards,
>  Ced

Thanks.
I have also an ASCII log on my serial device but it is harder to
understand, but more complete.
Your log file show me an important point in the IPCP communication.

So resume of my study of the new protocol AOL use.

It's a full PPP connection, internally AOL tunnel it with L2TP but we do
not have to care about it.

Client connect with the same phone number.
It send LCP request as normal.
LCP identification seems optionnal, it works without.
Authentication is done with CHAP login: aolip, password: l0app (doesn't
appears in your dump, don't know why)
Now problems start with IPCP dialog.
First AOL give you an IP but
  - this IP is not a normal 172.*.*.* AOL address
  - it's fully filtered. From what I've seen any IP packet sent result in
    an ICMP net unreachable return. So it's not useable.
What your dump show me is that there is a second IPCP dialog which give
you a valid IP (strange... we're not really authenticated, so I believe
it will be filtered for any external internet access, I think only AOL
network will be reachable)

When IP is configured, the client connect to a *.dial.aol.com host (to
be determined: how to now this host)
So real authentication is done here, similar to the old AOL protocol but
instead of P3, it's just UDP.
All AOL content (mail, welcome page, aim, etc...) is sent/received on this 
tunnel.

It's all what I can say from now.
I'm a bit locked because I don't know how to make pppd do 2 IPCP
request.

There is also some strange things in your capture, like NTP?
Just a question: are you using ADSL?

Thanks for your help.

JC

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