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Subject: Re: Unable to upload to S3 when pf is activated
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From: Kristof Provost <kp@FreeBSD.org>
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> On 14 Dec 2015, at 21:38, murdoch.john@moumantai.de wrote:
> yes, the machine runs on Amazon and yes again -tso fixed the problem.
>=20
> Could I have seen this somehow watching the pf log? Maybe package =
length?

It=E2=80=99d be hard to spot. The problem was related to the checksums, =
so you=E2=80=99d have to explicitly look for checksum errors.
To make it worse, you=E2=80=99d not spot the problem looking at tcpdump =
captures on the machine itself (because you=E2=80=99d see the =
pre-segmentation packets).

In effect, the best, if not only, way to spot it would be to set up a =
TCP connection to another machine you control and then send large chunks =
of data (to trigger TSO) and look at those checksums.

Regards,
Kristof=