Packet-corruption with re(4)

Peter Ankerstål peter at pean.org
Tue Apr 29 12:30:32 UTC 2008


On Apr 29, 2008, at 2:08 PM, Jeremy Chadwick wrote:
>>
>
> tcpdump reporting "bad cksum" can occur due to TX/RX checksum
> offloading.  Do you not see this message normally, but only when the
> problem begins?
>
> Have you tried turning off TX/RX offloading to see if the erroneous
> behaviour goes away?
>
> Have you tried disabling RFC1323 to see if that's actually what's
> responsible for the stalls you're seeing?  sysctl  
> net.inet.tcp.rfc1323=0
>
> I'd recommend staying away from Realtek NICs.  Pick up an Intel Pro/ 
> 1000
> GT or PT.  Realtek has a well-known history of issues.
>

Now Ive tried:
ninja# sysctl net.inet.tcp.rfc1323=0
net.inet.tcp.rfc1323: 1 -> 0
ninja# ifconfig re0 -rxcsum -txcsum -tso -lro

The problem remains, but when I have -rxcsum/tx tcpdump does not say  
anything
about bad checksums but it send out the same ack over and over.
and it seems like bigger files are the most effected (images rather  
then html-files)

I know, I have em in all other machines..  :/


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