[svlug] TCP checksum ignored?

Ira Abramov lists-svlug at ira.abramov.org
Sun Mar 23 08:12:44 PST 2003


for the second time in 4 months I bump into a blade in one of our blade
servers that ignores TCP packet errors quitely.

Scenario: files pulled over TCP (http, ftp) to the machine (mobile
Pentium 3, Intel e1000 interface) get there with a different md5sum each
time. tried both with machines on the same subnet as well as remote. the
second interface on that same blade works fine. I have no other
conclusion to reach but that the faulty interface not only changes the
occasional bit in the data, but both ethernet and TCP error detection
tests fail.

Is there a possibility that in order to cut CPU overhead, the kernel
defaults not to check crc32 on TCP packets? I saw this with three
different kernel versions as well, from SuSE, RH and virgin 2.4.20 from
kernel.org.

any ideas, anyone?

-- 
E-Book burner
Ira Abramov
http://ira.abramov.org/email/



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