Cryptic characters at 4kboundary after ssh transfer

Cryptic characters at 4kboundary after ssh transfer

[Caduff Claudio DFRKSTA]

Hi

We use cygwin for an encrypted transfer between network zones.
- used Servers: mixed (all 64-bit): Windows 2008 R2 Enterprise / Windows 2012 R2 Standard
- used Cygwin package version: mixed: 2.774 / 2.877
- used cygwin1.dll version: mixed 1.7.17 / 1.7.32 / 1.7.33 / 2.7.0
- used sshd version (info from sshd_config): mixed: 1.87 / 1.93

Since about one year we observe the following situation:
In some (about 1 of 100) of the transferred files there are cryptic characters (always 8 Bytes), always at an address which begins after 4k.
- This (as far as we know) did never happen with files smaller than 5MB
- There are no error messages
- we don't know if there were such 'miss-transfers' earlier and we suppose that we don't find all of these files because an automated process is analyzing thes files and the effect ist depending on the logical position of these 8 Bytes.
- we cannot reproduce the error: if we transfer the same original file again it is transferred correctly.

Does anybody know such an issue or even a solution?

Best Regards,
Claudio

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Re: Cryptic characters at 4kboundary after ssh transfer

[Richard H Lee]

On 08/12/2017 13:39, Caduff Claudio  DFRKSTA wrote:
> In some (about 1 of 100) of the transferred files there are cryptic characters (always 8 Bytes), always at an address which begins after 4k.

Could this be related to any mmap calls? Cygwin mmaps in 4k blocks, but 
the caveat is that they are aligned at 64k boundaries.

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