Possible bug in CerebusFTP 2.11? [Only one usage of each...]

Think you've found a bug in a BETA version of Cerberus FTP Server? Post a description here.
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Windoze User

Possible bug in CerebusFTP 2.11? [Only one usage of each...]

Post by Windoze User » Tue Jan 20, 2004 5:46 am

I have two machines on a local 100BaseT FDX switch - the server is a Win2k SP4 machine running CerberusFTP 2.11 just downloaded and installed today.

The client is a Macintosh running Fetch 3.0.3 and is connected via its
10BaseT link to the same switch as the Win2k machine.

Download speeds are excellent... easily saturated wire-speed.

Problem: When downloading a whole bunch of files that are between 200KB and 1.1MB, I sporadically get errors of the form:

Only one usage of each socket address (protocol/network address/port) is
normally permitted.

I am enclosing log fragments:

Tue Jan 20 02:26:34 2004 4 Incoming connection request on interface
192.168.1.150
Tue Jan 20 02:26:34 2004 4 Connection request accepted from 192.168.1.152
Tue Jan 20 02:26:34 2004 4 USER anonymous
Tue Jan 20 02:26:34 2004 4 PASS ***********
Tue Jan 20 02:26:34 2004 4 SYST
Tue Jan 20 02:26:34 2004 4 PWD
Tue Jan 20 02:26:34 2004 4 CWD c/Documents and
Settings/spambrat/Desktop/downloads/TestingApps
Tue Jan 20 02:26:34 2004 4 PWD
Tue Jan 20 02:27:34 2004 4 PORT 192,168,1,152,31,69
Tue Jan 20 02:27:34 2004 4 RETR 91c-07a.exe
Tue Jan 20 02:27:34 2004 4 Data connection established
Tue Jan 20 02:27:34 2004 4 File transfer complete
Tue Jan 20 02:27:34 2004 4 The data connection was closed by the remote socket
Tue Jan 20 02:27:34 2004 4 PORT 192,168,1,152,4,46
Tue Jan 20 02:27:34 2004 4 RETR 91d-16.exe
Tue Jan 20 02:27:34 2004 4 Data connection established
Tue Jan 20 02:27:34 2004 4 File transfer complete
Tue Jan 20 02:27:34 2004 4 The data connection was closed by the remote socket
Tue Jan 20 02:27:34 2004 4 PORT 192,168,1,152,152,111
Tue Jan 20 02:27:34 2004 4 RETR 91e-14.exe
Tue Jan 20 02:27:34 2004 4 Data connection established
Tue Jan 20 02:27:34 2004 4 File transfer complete
Tue Jan 20 02:27:34 2004 4 The data connection was closed by the remote socket
Tue Jan 20 02:27:34 2004 4 PORT 192,168,1,152,160,140
Tue Jan 20 02:27:34 2004 4 RETR 91f-01.exe
Tue Jan 20 02:27:34 2004 4 Data connection established
Tue Jan 20 02:27:35 2004 4 File transfer complete
Tue Jan 20 02:27:35 2004 4 The data connection was closed by the remote socket
Tue Jan 20 02:27:35 2004 4 PORT 192,168,1,152,113,49
Tue Jan 20 02:27:35 2004 4 RETR 91f-02.exe
Tue Jan 20 02:27:35 2004 4 Data connection established
Tue Jan 20 02:27:35 2004 4 File transfer complete
Tue Jan 20 02:27:35 2004 4 The data connection was closed by the remote socket
Tue Jan 20 02:27:35 2004 4 PORT 192,168,1,152,108,84
Tue Jan 20 02:27:35 2004 4 RETR 91f-24.exe
Tue Jan 20 02:27:35 2004 4 Data connection established
Tue Jan 20 02:27:35 2004 4 File transfer complete
Tue Jan 20 02:27:35 2004 4 The data connection was closed by the remote socket
Tue Jan 20 02:27:35 2004 4 PORT 192,168,1,152,175,50
Tue Jan 20 02:27:35 2004 4 RETR 91f-e.exe
Tue Jan 20 02:27:35 2004 4 Only one usage of each socket address
(protocol/network address/port) is normally permitted.


Tue Jan 20 02:28:15 2004 4 Connection terminated.
Tue Jan 20 02:28:15 2004 Shutting down local Interface 2 located at 192.168.1.150

I've tried enlarging the port # range in the settings to use 1025-60000, but
it has no noticeable effect. Sometimes the error happens quickly (under 100 files transferred) and sometimes it occurs after several hundred or a
thousand files have been transferred. I've tried it with and without the
TransmitFile API switch enabled in the Advanced tab.

Let me know if I can provide additional information to help you resolve this
issue.

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Serin
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Post by Serin » Sun Jan 25, 2004 11:51 pm

The error you are getting is most likely the result of the FTP client attempting to re-use a port that is still in the TCP delay state. After a socket connection is used and disconnected, TCP has a built-in delay that has to expire before that specific port/address can be reused. Most FTP clients simply increment the port they use on each subsequent PORT call, but a quick look at your log seems to point to the client selecting ports at random. It may be that when transfering a large amount of files, your client occasionally trys to reuse a port before the mandatory delay has expired. A different port is required for each file that is transferred.

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