ip4csum on wm - problems

Hi,

I have a problem with ip4csum on wm with
NetBSD-3.0_STABLE/xen (dom0) 
(should be probably same as i386).

After "ifconfig wm0 ip4csum" and sending ICMP
echo requests to this 
machine I am able to see both requests and replys with
tcpdump on this 
machine, on the sending machine I see only requests.
TCP4CSUM and 
UDP4CSUM work without problems, as everything else. Am I
doing something 
wrong? What can I do to debug this?

The device is:
wm0 at pci2 dev 3 function 0: Intel i82541GI 1000BASE-T
Ethernet, rev. 5
wm0: interrupting at irq 17, event channel 10
wm0: 32-bit 33MHz PCI bus
wm0: 256 word (8 address bits) MicroWire EEPROM
wm0: Ethernet address 00:0e:0c:6a:9f:59
igphy0 at wm0 phy 1: Intel IGP01E1000 Gigabit PHY, rev. 0
igphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX,
1000baseT, 
1000baseT-FDX, auto

# ifconfig wm0
wm0:
flags=8b43<UP,BROADCAST,RUNNING,PROMISC,ALLMULTI,SIMPLEX,
MULTICAST> 
mtu 1500
        
capabilities=87<IP4CSUM,TCP4CSUM,UDP4CSUM,TSO4>
         enabled=0
         address: 00:0e:0c:6a:9f:59
         media: Ethernet autoselect (100baseTX 
full-duplex,flowcontrol,rxpause,txpause)
         status: active
         inet 192.168.1.222 netmask 0xffffff00 broadcast
192.168.1.255
         inet6 fe80::20e:cff:fe6a:9f59%wm0 prefixlen 64
scopeid 0x1

Thanks,

r.

rudolf wrote:
> TCP4CSUM and UDP4CSUM work without problems, as
everything else.

Sorry, this is not very precise description, better(?):
With IP4CSUM, the machine acts as it doesn't send out any
packets. There 
are no problems with TCP4CSUM and UDP4CSUM.

r.