Subject: Problem with users connecting

From: Brett Goldstock <[email-masked]>
Date: Fri, 16 Jul 1999 17:50:34 -0400

I've recently (this week) started fielding calls from some of my 
users who are experiencing problems connecting to my ftp server. I 
was until recently running one of the VR versions, but now I'm 
current on 2.5.0.

The symptom is that the user can connect, but when a download is 
initiated, nothing happens. On my end, a check of the xferlog shows a 
zero byte incomplete download. This is for the most part users who 
are using a gui ftp client under Windows or Macintosh. Sometimes its 
a web browser, sometimes just an ftp client.

By no means is it happening to most of my users - it's perhaps 6-10 
out of about 1200 regular users. But it's odd that it suddenly became 
a problem. There seems to be no geographic correlation either. 
They're from Alaska, Ohio, Alberta, Mississippi and other places.

I really doubt it has anything to do with wu-ftpd, but I thought I 
would mention it to see if I could get any helpful suggestions.

thanks
-Brett

|Brett M. Goldstock                               [email-masked]|
|Senior Technical Analyst/Sys Admin          http://www.tvdata.com|
|TVData                                               800/833-9581|
|                "We tell the world what's on TV."                |

---

From: Gregory A Lundberg <[email-masked]>
Date: Fri, 16 Jul 1999 23:17:27 -0400

On Fri, Jul 16, 1999 at 05:50:34PM -0400, Brett Goldstock wrote:

> I've recently (this week) started fielding calls from some of my users
> who are experiencing problems connecting to my ftp server. I was until
> recently running one of the VR versions, but now I'm current on 2.5.0.
> 
> zero byte incomplete download. This is for the most part users who are
> using a gui ftp client under Windows or Macintosh. Sometimes its a web
> browser, sometimes just an ftp client.
> 
> By no means is it happening to most of my users - it's perhaps 6-10 out
> of about 1200 regular users. But it's odd that it suddenly became a
> problem. There seems to be no geographic correlation either.   They're
> from Alaska, Ohio, Alberta, Mississippi and other places.
> 
> I really doubt it has anything to do with wu-ftpd, but I thought I would
> mention it to see if I could get any helpful suggestions.

Do you have a client consistently having the problem?  If so, have them try
downloading from ftp.vr.net and ftp.wu-ftpd.org.  Both are running 2.5.0;
vr.net from inetd and wu-ftpd.org as a standalone.  That will tell us if
it's something consistent with 2.5.0 or their software/network.

You might also attempt to grab a tcpdump/snoop of one of their failing
sessions with your server.  At the same time, check your system logs for
messages which might be related.

If you would like, I can test against your server with IE5 and a Unix ftp
client.  Perhaps I'll have a problem or will be able to see something in
the way your deamon acts which might give a clue.

The only ongoing problem I'm currently seeing is there is a class of lamely
coded proxy/firewalls out there which is causing instances of the daemon
(only on wu-ftpd.org) to hang arround for indefinite periods of time.
Someone sent me a TCP keepalive patch for the daemon and I've tested it; it
helps some but indicates there may be another problem with idle timeouts
when running as a standalone daemon.  I have examined these sessions, even
capturing one entering the state; everything was normal and files
transferred fine.  It appears the remote software walked away from the FTP
session after the file transfer completed (indicating it was a web browser,
probably Internet Explorer) and the proxy never noticed the client was
gone.

-- 

Gregory A Lundberg              WU-FTPD Development Group
1441 Elmdale Drive              [email-masked]
Kettering, OH 45409-1615 USA    1-800-809-2195