Subject: Re: Multicast and hardware checksum

From: Baruch Even <[email-masked]>
Date: Fri, 08 Jun 2007 14:33:07 +0300

Baruch Even wrote:
> Herbert Xu wrote:
>> On Fri, Jun 08, 2007 at 02:02:27PM +0300, Baruch Even wrote:
>>> As far as IGMP and multicast handling everything works, the packets 
>>> are even forwarded over the ppp links but they arrive to the client 
>>> with a bad checksum. I don't have the trace in front of me but I 
>>> believe it was the UDP checksum that failed.
>>
>> What kind of a ppp device is this?
>>
>> If you run a tcpdump either side of the ppp link do you see the same
>> UDP checksum value?
> 
> This is a pptp link. I've checked the checksum on the receive side, I 
> don't know on the sender side and I'll only be able to try it on Sunday.

For completeness, the clients are Windows XP clients and the server is a 
  Linux machine. The tunnel is mppe encrypted so I believe that what 
goes out on the client is the same as what got in on the server.

Baruch