[pf4freebsd] Re: Strange problem/Need help

[Hendrik Scholz]

Hi!

Max Laier wrote:
>  It turned out (after days of brainwracking debugging) that
> the problem went away by disabling the i386 optimized version of in4_cksum(). 

Did you take into account that certain network cards do checksums in 
hardware?

[0.27] hscholz at deimos:~ > ifconfig xl0
xl0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
         options=9<RXCSUM,VLAN_MTU>

bge(4) and other good 10/100 and Gbit cards do even more so if the
TXCSUM option is enabled bpf sees packets with broken checksums as these
are calculated by the NIC itself before sending.

Just my $.02,
	Hendrik