Wake-on-lan packages don't get through

[Markus Hitter]

Am 16.12.2008 um 20:13 schrieb Paul Schenkeveld:

> On Tue, Dec 16, 2008 at 07:22:39PM +0100, Markus Hitter wrote:
>>
>> 18:50:30.019039 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF],  
>> proto UDP
>> (17), length 130) piccard.jump-ing.de.37597 >  
>> 255.255.255.255.40000: [bad
>> udp cksum b716!] UDP, length 102
>>
>> This package woke the targeted Macintosh. Doing the same on the  
>> embedded
>> Flepo, I get:
>>
>> 01:38:35.500497 IP (tos 0x0, ttl 64, id 40022, offset 0, flags  
>> [none],
>> proto UDP (17), length 130, bad cksum 0 (->d401)!) git.jump-ing.de. 
>> 50582 >
>> 255.255.255.255.40000: [bad udp cksum a1e4!] UDP, length 102
>>
>> The later doesn't get through the switch, I can capture it on the  
>> sending
>> host only. Accordingly, the Mac keeps sleeping.
>
> Please show a tcpdump -e output here.

(did that privately)

> What about the kernels, are they the same version?  and does your
> embedded system have more than one ethernet interface?

These two machines have different hardware, and the kernel of the  
embedded box is stripped, so yes, this might be different kernel  
behaviour. What bugs me is: neither ethernet package contains correct  
checksums. How is this possible if normal network operations  
obviously work just fine? Do I really have to debug the kernel  
driver? It's the "re" driver.


MarKus

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Dipl. Ing. Markus Hitter
http://www.jump-ing.de/