can't send raw frame when size is higher than 1500

[William Paule via dev <dev () nmap org>]

Dear Nmap developers,

Thanks for your library. It helps us a lot for our development.

I would like to share with you the issue we had using your library:

We are using your tool to send Ethernet frame to our device under test from
a windows 10 computer.
we need to work at layer 2 in order to fully control the payload we send.
(we have an homemade protocol for the L3)

On our machines, using the different examples provided with the library, it
was not possible to send frames with frame size greater than 1500. (we get
back an error from the DLL).

We tried the following examples:
sendpacket.c  (increasing maximum size from 100 to 1514)
and then
TestPacketSend.c (ex: with -s 1501)

in both cases the PacketSendPacket returns error code (we get the same
error message).

rem: It is an issue for us because we need to reach the maximum ethernet
frame size for our tests.

By chance, we finally managed to send bigger frames in 2 steps:
- enabling the jumbo frame (in the adapter parameters)
- executing the following function in the TestPacketSend.c  :
 PacketSetMode(lpAdapeter, 2);

For the moment it works fine on 2 different computers. But I think it is
more a workaround than the correct solution. I guess we disabled 2
successives protections... so I'm not fully satisfied.

Maybe we are missing something...
Moreover it is strange that the examples provided with the libray get the
issue...
I'm wondering if we  have an issue with the Ethernet board drivers

here is my question:
did you already have such issue?
would you have an idea what could be the correct settings we need?

Thanks a lot for your work.

best regards

William

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