checksums on http transfers?

A while ago, when we were discussing checksums, we were thinking of adding
checksums to the repository, to ensure that we could accurately reconstruct
old versions. At the same time there was a little bit of discussion about
checksums on the network traffic as well.

IIRC it was decided that checksums weren't really important for network
traffic, since tcp was already checksummed. However, I have been thinking.
my recent working copy problems seem to have stemmed from the following:
My ISP performs NAT somewhere in its network, which requires re-caculating
the tcp checksum of packets as they pass through. It seems that the
problem is that they weren't _verifying_ the original checksum before
recalculating, therefore allowing corrupted packets to be received by
my machine.

In light of this, I thought I would bring this subject up again. I was
wondering does http have an md5sum header or something, and how would we
go about making mod_dav_svn generate and send this header, and have
neon verify it. gstein, joe, any pointers? I'd be willing to take on
this challenge, just to make sure I don't get any more wonky working copies
if my ISP's NAT goes flaky again.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Kevin Pilch-Bisson                    http://www.pilch-bisson.net
     "Historically speaking, the presences of wheels in Unix
     has never precluded their reinvention." - Larry Wall
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