Re: Linux TCP problem while talking to hostme.bkbits.net ?

David S. Miller (davem@redhat.com)
Mon, 12 Aug 2002 02:54:53 -0700 (PDT)


From: Meelis Roos <mroos@linux.ee>
Date: Mon, 12 Aug 2002 10:28:10 +0300 (EEST)

Before and after the connetion attempt - looks like the number of bad
segments is increasing so probably not a TCP bug.

Since I can connect to this server fine from different locations, it
looks like something (ISP caches/shapers? cable modem?) is corrupting
specific packets in a reproducible way.

Aparently something is wrong with the checksums.
InErrs gets incremented in three cases:

1) Header too small, unlikely what you see

2) Bad SYN sequences, Abort On Syn in TcpExt would have been
incremented also if this were the case, it was not

3) Bad TCP checksum

Hmmm, do you have messages that say "hw tcp v4 csum failed"
in your kernel logs? Any other interesting kernel messages?
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