On 2007-10-09, Eric.M.Martinez@gmail.com wrote:
> I'm trying to checkout a moderately sized project from a remote CVS
> repository over SSH. I've done this several times before with various
> machines, but now I'm having problems. I execute:
>
> cvs checkout
>
> And the checkout begins, but after about 50 files or so, I get the
> following error:
>
> Disconnecting: Corrupted MAC on input.
> cvs [checkout aborted]: end of file from server (consult above
> messages if any)

What this means is that one end of the connection things that the data
has been corrupted in transit ie the MAC (Message Authentication Code,
think: checksum on steroids) does not validate.

Unfortunately there's many possible causes. Of the ones that have been
determined:

- routers corrupting packets
- flaky ethernet cards/drivers
- flaky RAM

Of the other possible causes which have never been proven (however there
are unresolved instances):
- bad openssl builds (possibly compiler bugs?)
- bugs in TCP stacks
- bugs in OpenSSH

See the following for documented cases:
https://bugzilla.mindrot.org/show_bug.cgi?id=510
https://bugzilla.mindrot.org/show_bug.cgi?id=845

> I've read several posts claiming incompatible openssh/ssl versions,
> but I don't think that is the problem because I have the same openssh/
> ssl version combinations on a different machine, and I have had no
> trouble with that.

It shouldn't be that, however if someone was having that problem and
during an upgrade replace a problem binary with a working one it could
be misinterpretted as that.

--
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4 37C9 C982 80C7 8FF4 FA69
Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.