NIC capable of receiving Corrupt frames

Hardware Questions and Recommendations
1

I am working on a project which requires me to capture packets that don't pass the CRC 32 check. I did some digging and came across ethtool utility, using which we can change ethernet device parameters.

To allow the capture of packets, which do not pass the CRC 32 I need to use the following command:

ethtool -K DEVname -fcs on

ethtool -K DEVname -rx all on

However, for most NICs this option is fixed.

I need help finding cards that are capable of changing the -rx all option. Also, How can we check if a particular card has the option non-fixed, before purchasing it as I was unable to find documentation that explicitly specifies this. I am looking for cards that have open source wireless drivers such as the atheros ath9k.

I am looking to capture packets over wireless media on promiscuous/monitor mode. But I want the NIC to send me the corrupt ones as well, i.e. I want to bypass the CRC check

Thanks in advance.

2

@mgb17, welcome to the community!

I thought that's what monitor mode did. In fact, the Wiki clearly states this:

So, since you're aware ath9k chips can do so...what's the concern?

1 Like
3

Thank you for the welcome!

I am just a little confused about the monitoring mode, I read at many places that the NIC drops the corrupt packet and the corrupt packet never reaches the OS, in the first place so monitor mode is not very helpful. Many forums/articles said it's not possible to do so. However, I found 2 other solutions-

  1. ethtool that I mentioned above but it is fixed for most cards
  2. setting the fcs fail flag in monitor mode.

So I thought it would be best to ask about the ethtool as well.

I will try monitor mode out and reach out if I need help.

Thanks!