I’ve spend almost an hour trying to isolate a problem that persisted with slow ftp transfers .
First I thought the slowness is because of some kind of firewall rules, anyways I’ve tested disabling the iptablesfirewall rules and the effect was absolutely the same.
I was able to login normally to the newly configured vsftp server on Debian installed through:
debian-server:~# apt-get install vsftpd
The vsftp is configured to run as a stand alone service and not via inetd. A copy from the non-working vsftpd.conf can be obtained from here
I couldn’t find any fault or misconfigured variable in the above mentioned ftp configuration file.
The file doesn’t contain neither a syntax nor logical errors. The Vsftpd service was running as a daemon perfectly fine.
I read online about some suggestions that something could be wrong with my /etc/hosts.allow or /etc/hosts.deny files but neither of them doesn’t contained any deny rules.
Though I tried entering the following line to /etc/hosts.allow:
vsftpd: ALL: ALLOW
Guess what nothing changed, the uploading slowness and the error message:
421 Service not available, remote server timed out. Connection closed
was at hand.
I tried even transffering data files on localhost whilest the firewall was disabled using:
debian-server:~# ftp 0
Connected to 0 (0.0.0.0).
user: hipo
pass: *********
ftp>put file.tar.gz
229 Entering Extended Passive Mode
150 Ok to send data.
421 Service not available, remote server timed out. Connection closed
I also tried raising up the data_connection_timeout which by default was equal to 120 secs to data_connection_timeout=720
This doesn’t help as well. Lest that I tried also to fix the issue through changes in the following vsftp variables:
connect_from_port_20=NO
xferlog_enable=NO
local_max_rate=50max_per_ip=40
max_clients=50
Nomatter what I tried the shitty transfer timeout error was determined to reappear:
421 Service not available, remote server timed out. Connection closed
Pretty much like problems passing through an arcade game super-boss ! ghh ..
Following some forum suggestions that might help resolving the error I tried also the vsftpd conf variables:
pasv_enable=YES
pasv_min_port=11000
pasv_max_port=11010
Again the 421 Service not available, remote server timed out. Connection closed during a file transfer occured!
That completely pissed me off, so I did a radical decision. Just wipe out vsftpdand exchange it for the easier to implement and less problematic good old PROFTPD
My experience with proftpd as a server ftp daemon was most of times positive. It was luckily like this also this time!
The swith to proftpd on the server was a piece of a sweety cake:
debian-server:~# apt-get install proftpd
There you go now transfer works and the 421 Service not available, remote server timed out. Connection closed is solved in a radical and very easy manner!
Yet if you continue experiencing some kind of data transfer errors or ftp login errors I recommend you load the nf_conntrack_ftp if you’re running linux kernel > 2.19, if you’re using an older kernel version then you should load the ip_conntrack_ftp kernel module.
To make kernel loadable during system boot time do execute:
debian-server:~# echo nf_conntrack_ftp >> /etc/modules
To prevent FTP data transactions caused by iptables firewall rules I suggest you also check my article Iptables Open FTP Port 21 and 20 to enable your Linux firewall in and out FTP server data transfer to flow
