[Dnsmasq-discuss] dnsmasq v2.40: pxe network boot is failing

Wayne Sherman wsherman at gmail.com
Tue Jan 8 13:24:21 GMT 2008

Simon Kelley wrote:
> 1) I don't think there's any configuration problem: DHCP is working 
> fine, and the client seems to be trying to do the right thing.
> 2) TFTP seems to be failing. TFTP is a pretty simple-minded protocol, so 
> it's fairly easy to trace what's going on in a packet-trace captured 
> using wireshark.

Good suggestion.  It took me awhile to dig up a hub, but I finally ran 
some packet capture tests and found out the problem.  Many of the tftp 
packets (UDP) from my server to the client had UDP checksum errors. 
Wireshark suggested it might be caused by UDP Checksum offload.  I 
removed offloading on the server NIC (Realtek RTL8111B - r8169 driver) 
using Ethtool:

   ethtool -K eth0 rx off tx off sg off tso off gso off

and now it works fine.

Perhaps this is a r8169 driver or kernel bug.

> 5) You say that your server is gigabit and the client 10/100. What's 
> doing the rate-adaption...
(my switch is 10/100 so gigabit NIC is running in 100Mbit mode)

Thanks for your help,


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