Re: [Proftpd-user] Directory listing fails

This issue is happing on multiple networks with multiple different FTP 
clients trying to access the same account/directory, so we can rule out 
network/client issues.

Nowhere in my proftpd.conf file is there any mention of timeout settings.

Other ideas?

	- John

On 3/5/17 9:33 PM, TJ Saunders wrote:
>
>> Unfortunately not, as I don't have a specific example off the top of my
>> head.  I do know we've had clients request PureFTPd's preferences be set
>> to display a larger number of files in the past.
>
> OK.  The reason I ask is that you mentioned that you had not explicitly
> set any ProFTPD's timeout directives (TimeoutIdle, TimeoutStalled,
> TimeoutNoTransfer, etc).  And you mentioned that now, you are seeing
> "Remote host has closed the connection." after 60 seconds.
>
> None of ProFTPD's timeouts have a default setting of 60 seconds.  Which
> makes it curious what could be causing this.  The ProFTPD debug logging
> would show if the above 60 second loss of connectivity was, in fact,
> caused by some timeout.  If not, then it would suggest that something in
> between the client and the server is closing the connection.
>
> I've seen this sort of thing happen before, with FTP-unaware
> firewalls/NAT, which would close the FTP control connection for being
> idle (whilst the client was waiting for traffic on the separate data
> connection); such network middleboxes don't know to associate FTP's
> separate control and data TCP connections together.
>
> Now if _this_ is the case, making it work with ProFTPD becomes a little
> harder -- and more likely to cause other problems with FTP clients.  For
> it would mean that ProFTPD would need to "trickle" data on the control
> connection -- an on-going multiline response for the LIST command, in
> order to keep that control connection alive.  And I'm not sure how well
> FTP clients would react to that sort of thing, in that situation.
>
> So right now, it looks like it's either a) a ProFTPD timeout that you're
> unaware of, somewhere in your config, which is causing the connection to
> close, or b) it's something in the network.  And we'll need more data
> (e.g. the proftpd debug logging) to be sure.  If you'd had this working
> with a different FTP server, we could compare the transcripts and see
> what that server might be doing differently (was it trickling responses
> on the control connection, for example?  Was the client in question
> using FTP keepalives[1]? etc).
>
> Cheers,
> TJ
>
> 1. http://www.proftpd.org/docs/howto/KeepAlives.html
>
>


-- 

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Point In Space Internet Solutions         800.664.8610 919.338.8198


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