Deprecation of scp protocol and improving sftp client

Markus Friedl mfriedl at
Tue Jun 23 16:06:43 AEST 2020

I had something in mind like this for years, but with slightly different steps:
My naive approach would be to keep the scp user interface and switch
to the sftp protocol internally. We could add a -M [scp|sftp] option
to scp and select the internal protocol. Later we switch the default
from scp to sftp.
No need to change sshd or write scpd.


Am Di., 16. Juni 2020 um 18:48 Uhr schrieb Jakub Jelen <jjelen at>:
> Hello all,
> I believe we all can agree that scp is ugly protocol carried for ages
> only for its simplicity of its usage and really no dependencies as it
> is installed together with every ssh client. But as we have seen
> recently, its simplicity and flexibility comes with security issues
> [1], it does not have great performance and there is really no
> development in there.
> Over the years, we still keep recommending people to use sftp instead,
> but its api is not that flexible and simple to be usable as a drop-in
> replacement in scripts nor for the occasional ad-hoc transfers of few
> files from one server to another.
> Before I start hacking, I would like to hear some opinions from others,
> whether this is something planned, welcomed or whether there are some
> good reasons to keep scp alive.
> I have in my mind three things/steps that would make it possible:
>  * Update sftp client to be drop-in replacement for scp
>    (and/or)
>  * Change scp to use sftp internally
>  * Modify sshd to use some compatibility "scpd" to support old clients
> and some time later
>  * Remove scp or replace it with a symlink
> [1]
> Any ideas/comments/suggestions?
> Best regards,
> --
> Jakub Jelen
> Senior Software Engineer
> Security Technologies
> Red Hat, Inc.
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> openssh-unix-dev at

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