Re: [Proftpd-user] Prooftpd corrupts my ogg-files

Hi Goran,

One can always increase the log level:
http://www.proftpd.org/docs/howto/LogLevels.html
In this case I suspect that there is one of two things happening here. The
client for whatever reason tries to push the files as ASCII rather than
binary data which would most certainly corrupt the files. Or the clients
are chopping up the files using more than one connection to upload (or
disconnecting and reconnecting to resume the uploads) and this is for some
reason causing the files to be corrupted.
A third option is that the clients used are not telling the truth when
setting up the initial connection. There are many versions of the protocol
possible and I have seen in the past that proftpd negotiated with the
client to use protocol version 6 where as soon as certain protocol version
6 commands were sent the client panicked and disconnected. This is why you
can based on the client identifier and client version force a certain
protocol and other parameters of the connection. See:
https://forums.proftpd.org/smf/index.php?topic=4616.0 for a decent
explanation. I have found that forcing version 3 of the protocol with a 1GB
window size is in 99% of the cases I have encountered a safe setting.
Since there is a difference in behaviour between vsftpd and proftpd I guess
this might be where the problems are coming from. And vsftpd simply knows
that some clients lie about their capabilities thus sets up a different
protocol version and window size even though the client claims it can do
better.

Since I am 100% certain that partial uploads are working perfectly fine
with proftpd and it is the client that decides if a file is uploaded as
ascii or binary I think that increasing the logging might give you a good
insight into what is going on.

The easiest way to figure this out in the logs is if you can control who
connects when and have just a single session you know is going to corrupt a
file going. If not proftpd assigns every connection a unique ID (unique for
the duration of the connection the ID's are reused thoughout the day/week)
so you can use that to grep all messages relevant to that session and see
exactly what happened when the file was being uploaded.

Regards,

Rob

On Mon, Jan 18, 2021 at 9:25 AM Goran Hasse <[email protected]> wrote:

> Hello,
>
> I am transfering a lot of ogg-files from clients to the server. Quite
> often proftpd corrupts those files. (I have changed to vsftpd - and the
> problem dissapeared).
>
> The logging is a little bit to week to figure out what is going on. Any
> idea on how to investigate this?
>
> // GH
>
> --
> Göran Hasse
> Raditex Control AB
> email: [email protected]
> Mob: 070 5530148
>
>
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