Hi there. I'm experimenting many disconnections when uploading files on Internet through ftp.proxy and some firewalls. After some tests, I find out that when I disable buffering within ftp.proxy (-z 1) the problem does no longer occur.
As the disconnection occurs only at the end of uploads (STOR), when the server give several sucessives answers (codes 125 and 226), I suppose that in some configuration, the buffering can lead to IP packets re-arrangement that my firewalls dislike (they do statefull firewalling and disallow non-FTP protocols on FTP ports and are very narrow-minded about what FTP is). To be precise, the problem occurs only with small files (in my case <14kB but that may vary), and I suppose that those small files are the only ones for which 125 and 226 answers are close enough to be re-arranged, since for other files the transfer is too long. I hope this will help someone. If someone as already experienced the same problem and/or found another workaround, please tell me. Here is a patch proposal for ftp.proxy man page. Andreas, if you do agree with it, you can take it for next versions. Regards. -- Gregoire Barbier - gregoire.barbier(at)free.fr - +33 6 21 35 73 49 --- ftp.proxy.1.original Fri Jan 10 00:27:59 2003 +++ ftp.proxy.1 Fri Jan 10 00:34:57 2003 @@ -248,6 +248,10 @@ The default is 1024 bytes, valid values range from 1 to 4096. Playing around with larger values than the default may increase the proxy's data troughput. + +This buffering can lead to re-arrange IP packets on the network, so if +you use both \fIftp.proxy\fR and firewalls with statefull packet filtering of +FTP protocol, and you encounter many disconnections, try to set -z to 1. .PP .SH "SYSLOG" \fIftp.proxy\fR reports to FTP log facility.
