Subject: Re: `ifconfig wm3 ip4csum` creates bad cksums via tcpdump
To: Paul Goyette <>
From: Charlie Allom <>
List: current-users
Date: 05/19/2007 20:48:58
On Sat, May 19, 2007 at 11:24:14AM -0700, Paul Goyette wrote:
>  If the tcpdump is for an outbound packet, this is expected.  Since you told 
>  the driver that the hardware does checksum, the software doesn't
>  calculate one;  it just sets it to zero.  Then tcpdump gets its copy of

aha - thank you!

>  the packet and dumps that out.  Sometime later, the hardware gets to do its 
>  thing and calculates the correct checksum.
>  Get the tcpdump from the receiving side and verify there that the csum is 
>  good.

indeed. all seems well at the end of the day :)

Thanks Paul.

 hail eris