Re: SFTP client Expect 5.43 via PASE intermittently failing

[Tim Bronski <tim.bronski@xxxxxxxxx>]

> 2) Could the DOS attacks be slowing down the SFTP handshake process, thus not allowing it to complete in its required time interval X, whatever X is?
X is the login grace time that's set in the server's sshd config. The default is 120 seconds. The login process should be sub second. 40 failures in 60 days is extraordinarily high.


On 1/20/2016 6:45 AM, Steinmetz, Paul wrote:
> I have an SFTP client Expect 5.43 via PASE intermittently failing.
> This process runs every 15 minutes, 6 am to 9 pm, Sun thru Sat, so about 60 times per day.
> 40 failures since 11/20, when this converted from an FTP to SFTP.
>
> When it fails, I get this error message.
>
> ssh_exchange_identification: read: Connection reset by peer
> Connection closed
>
> The remote side has not found any issues on their side.
> We haven't found any issues on our side.
>
> What was discovered that at the same time of some of the failures, our ISP was having DOS attacks.
>
> My question is two-fold.
> 1) During the initial SFTP handshake process, how long does this normally take?
> 2) Could the DOS attacks be slowing down the SFTP handshake process, thus not allowing it to complete in its required time interval X, whatever X is?
>
> Thank You
> _____
> Paul Steinmetz
> IBM i Systems Administrator
>
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