SFTP Protocol, extension: Hash value of file

[Thomas Guettler]

Hi,

I suggest to improve the sftp protocol: It would be nice
to get a hash value (maybe sha1). This way a client can check
if it needs to get the file, without transfering it.

The status of the ietf draft is "expired":
http://tools.ietf.org/wg/secsh/draft-ietf-secsh-filexfer/

Is any one still working on the draft?

I only use OpenSSH. For me it would be enough to integrate it there.
But as standard it would be better.

Thomas G�ttler

--
Thomas Guettler, http://www.thomas-guettler.de/
E-Mail: guettli (*) thomas-guettler + de

[Helmut Jarausch]

Thomas Guettler wrote:
> Hi,
>
> I suggest to improve the sftp protocol: It would be nice
> to get a hash value (maybe sha1). This way a client can check
> if it needs to get the file, without transfering it.
>
> The status of the ietf draft is "expired":
> http://tools.ietf.org/wg/secsh/draft-ietf-secsh-filexfer/
>
> Is any one still working on the draft?
>
> I only use OpenSSH. For me it would be enough to integrate it there.
> But as standard it would be better.
>
> Thomas G�ttler
>

What about using rsync via ssh, e.g.
to upload changed files

pushd <Source directory>
rsync -avz --rsh=ssh --checksum --delete . DESTINATION:<Dest Directory>/
============================ important ================================^

or the other way round (note the dot at the end)

rsync -avz --rsh=ssh --checksum --delete DESTINATION:<Dest Directory>/ .
============================ important ==============================^

rsync is very clever at transmitting as few as possible.

--
Helmut Jarausch

Lehrstuhl fuer Numerische Mathematik
RWTH - Aachen University
D 52056 Aachen, Germany

[Thomas Guettler]

Helmut Jarausch wrote:
> Thomas Guettler wrote:
>> Hi,
>>
>> I suggest to improve the sftp protocol: It would be nice
>> to get a hash value (maybe sha1). This way a client can check
>> if it needs to get the file, without transfering it.
>>
>> The status of the ietf draft is "expired":
>> http://tools.ietf.org/wg/secsh/draft-ietf-secsh-filexfer/
>>
>> Is any one still working on the draft?
>>
>> I only use OpenSSH. For me it would be enough to integrate it there.
>> But as standard it would be better.
>>
>> Thomas G�ttler
>>
>
> What about using rsync via ssh

I know rsync, I use it daily. Nevertheless I think it would be nice to
get the hash value of a file.

If you have a "sftp-only" account (no shell login, no permission to start rsync),
you could implement something like rsync using the sftp protocoll.

Thomas

[Helmut Jarausch]

On 11/13/09 12:24, Thomas Guettler wrote:
> Helmut Jarausch wrote:
>> Thomas Guettler wrote:
>>> Hi,
>>>
>>> I suggest to improve the sftp protocol: It would be nice
>>> to get a hash value (maybe sha1). This way a client can check
>>> if it needs to get the file, without transfering it.
>>>
>>> The status of the ietf draft is "expired":
>>> http://tools.ietf.org/wg/secsh/draft-ietf-secsh-filexfer/
>>>
>>> Is any one still working on the draft?
>>>
>>> I only use OpenSSH. For me it would be enough to integrate it there.
>>> But as standard it would be better.
>>>
>>> Thomas G�ttler
>>>
>>
>> What about using rsync via ssh
>
> I know rsync, I use it daily. Nevertheless I think it would be nice to
> get the hash value of a file.
>
> If you have a "sftp-only" account (no shell login, no permission to start rsync),
> you could implement something like rsync using the sftp protocoll.
>

I don't know about an sftp-only account. Have you tried
rsync -avz --rsh=ssh --checksum --delete <HOST>:<DIRECTORY>/ <LOCAL DIRECTORY>

I don't think you need a shell account to run that. AFAIK this is handled by
the sshd daemon on <HOST> which is needed for sftp, as well.

Helmut.