Ethereal-users: [Ethereal-users] no PPP header for IP over PPP?

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From: "Rudolf Zarits (privat)" <rudolf.zarits@xxxxxxxxx>
Date: Fri, 12 Mar 2004 04:47:23 +0100
Hi,

I´m new in the list and hope to find here some
clarification :

I´m using ethereal on Linux and Windows -
Following Configuration:

- Windows XP
- winpcap 2.3
- USB -> Bluetooth converter
- Bluetooth GPRS MS

between laptop and the MS PPP is used for
configuration and transport -
when i start communication between the laptop and
the GPRS MS (which can be considered as modem)
i see all the traffic like I supposed it to be:
PPP IPCP and PPP LCP messages for the configuration
of the link between the MS and the laptop -

after the laptop has "its" IP address assigned, I expected
the traffic to be "IP over PPP", which means that a PPP header
should be present -
but what I see is plain IP - without any PPP header!?!?!?
How is that possible?
Is the PPP header removed before tcpdump captures the packets,
or is there really plain IP (without PPP header) used between laptop
and MS (which in my opinion is not possible)...

Can anyone give me a clarification what exacly happens here?
thanks in advance
rudolf

PS: If this is the wrong place for this kind of questions and
you know a better one, pls don´t hesitate to tell me!

here is the beginning of the transfer, until the "plain" IP starts...

Frame 1 (37 bytes on wire, 37 bytes captured)
Ethernet II, Src: 20:53:45:4e:44:02, Dst: 20:53:45:4e:44:02
PPP Link Control Protocol

...
...
...

Frame 12 (24 bytes on wire, 24 bytes captured)
Ethernet II, Src: 20:53:45:4e:44:02, Dst: 20:53:45:4e:44:02
PPP Compression Control Protocol

Frame 13 (54 bytes on wire, 54 bytes captured)
Ethernet II, Src: 20:53:45:4e:44:02, Dst: 20:53:45:4e:44:02
PPP IP Control Protocol

Frame 14 (30 bytes on wire, 30 bytes captured)
Ethernet II, Src: 20:52:45:43:56:02, Dst: 20:52:45:43:56:02
PPP Link Control Protocol

Frame 15 (54 bytes on wire, 54 bytes captured)
Ethernet II, Src: 20:53:45:4e:44:02, Dst: 20:53:45:4e:44:02
PPP IP Control Protocol

....
....
....

Frame 22 (30 bytes on wire, 30 bytes captured)
Ethernet II, Src: 20:52:45:43:56:02, Dst: 20:52:45:43:56:02
PPP IP Control Protocol

Frame 23 (54 bytes on wire, 54 bytes captured)
Ethernet II, Src: 00:00:02:00:00:00, Dst: 02:65:20:00:02:00
MDS Header(Unknown(0)/Unknown(0))
    MDS Header
    MDS Trailer
[Malformed Packet: FC]

Frame 24 (342 bytes on wire, 342 bytes captured)
Ethernet II, Src: 00:00:02:00:00:00, Dst: 02:65:20:00:02:00
Internet Protocol, Src Addr: 80.187.67.202 (80.187.67.202), Dst Addr:
255.255.255.255 (255.255.255.255)
User Datagram Protocol, Src Port: bootpc (68), Dst Port: bootps (67)
Bootstrap Protocol

....
....

<comment: just plain IP (no PPP header) like frame 24 for the whole
transfer!>

...
...
...