Wake-on-lan packages don't get through

[Markus Hitter]

Hello all,

glad to have found a binary[1] wake-on-lan program, I obvserve  
different behaviour of /usr/bin/wol on my full-size FreeBSD and my  
TinyBSD. From the full-size BSD (VirtualBox on Linux), i could  
capture this package after issueing wol:

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.


As both "wol" binaries are the very same (copied), I can rule out  
compilation errors. To be more funny, the Flepo serves web pages just  
fine. What does go wrong here?


Thanks for any enlightenment,
Markus



[1] Using wakeonlan requires Perl, which in turn would more than  
double the size of the installation on the embedded box.

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