vsftpd remote connections

[Kirsle]

Hi, on my current server install of CentOS 5, vsftpd seems to be pretty instable when handling remote connections.

When I connect from within my local network, via Nautilus, it brings up the login prompt and I log in and see the root / of the server and everything is fine. However, when I attempt to log in from somewhere else on the Internet, the results are inconsistent.

I've never been able to log in through Nautilus from a remote IP address. It will prompt for the login info, but then just show a blank directory. If I log in as anonymous, I see the "pub" folder and the default anon FTP files and everything works fine, it's just when I log in as a user does it act weird like that.

I tried connecting with FireFTP (Firefox addon), and what appears to be happening is, FireFTP connects and logs in, but when it tries to get a directory listing it says it's going into passive mode and then that it's been disconnected from the server.

When I use the ftp client in the terminal, the results are inconsistent. I can always connect to the server, log in and be presented with my login prompt. If I use the `pwd` command, it prints the path to my home directory (which is the expected behavior). However, a `dir` or `ls` ends up disconnecting me about 50% of the time.

For instance:

[kirsle@eclipse ~]$ ftp cuvou.com
Connected to cuvou.com.
220 (vsFTPd 2.0.5)
530 Please login with USER and PASS.
530 Please login with USER and PASS.
KERBEROS_V4 rejected as an authentication type
Name (cuvou.com:kirsle): kirsle
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> pwd
257 "/home/kirsle"
ftp> dir
421 Service not available, remote server has closed connection
Passive mode refused.  Turning off passive mode.
No control connection for command: Transport endpoint is not connected

ftp> open cuvou.com
Connected to cuvou.com.
220 (vsFTPd 2.0.5)
530 Please login with USER and PASS.
530 Please login with USER and PASS.
KERBEROS_V4 rejected as an authentication type
Name (cuvou.com:kirsle): kirsle
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> pwd
257 "/home/kirsle"
ftp> dir
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
-rw-------    1 500      500       1061478 Jan 12 12:46 01.bmp
-rw-------    1 500      500       1061478 Jan 12 12:46 02.bmp
-rw-------    1 500      500       1061478 Jan 12 12:46 03.bmp
-rw-------    1 500      500       1061478 Jan 12 12:46 04.bmp
-rw-rw-r--    1 500      500         26220 Dec 28 23:01 save_the_day_13.jpg
-rw-rw-r--    1 500      500        144426 Dec 28 18:20 sonic_071225b-l.jpg
-rw-rw-r--    1 500      500        771582 Jan 12 23:11 ss.png
-rw-------    1 500      500           228 Dec 11 04:40 test.pl
-rw-------    1 500      500             0 Dec 11 04:39 test.pl~
226 Directory send OK.
ftp>

Anybody know why this might be happening? I've tried uninstalling/reinstalling vsftpd but it didn't help. It may be the config files but I'm not sure. I don't think I've edited the config since I originally installed it.

[root@epsilon vsftpd]# cat vsftpd.conf 
# Example config file /etc/vsftpd/vsftpd.conf
#
# The default compiled in settings are fairly paranoid. This sample file
# loosens things up a bit, to make the ftp daemon more usable.
# Please see vsftpd.conf.5 for all compiled in defaults.
#
# READ THIS: This example file is NOT an exhaustive list of vsftpd options.
# Please read the vsftpd.conf.5 manual page to get a full idea of vsftpd's
# capabilities.
#
# Allow anonymous FTP? (Beware - allowed by default if you comment this out).
anonymous_enable=YES
#
# Uncomment this to allow local users to log in.
local_enable=YES
#
# Uncomment this to enable any form of FTP write command.
write_enable=YES
#
# Default umask for local users is 077. You may wish to change this to 022,
# if your users expect that (022 is used by most other ftpd's)
local_umask=022
#
# Uncomment this to allow the anonymous FTP user to upload files. This only
# has an effect if the above global write enable is activated. Also, you will
# obviously need to create a directory writable by the FTP user.
#anon_upload_enable=YES
#
# Uncomment this if you want the anonymous FTP user to be able to create
# new directories.
#anon_mkdir_write_enable=YES
#
# Activate directory messages - messages given to remote users when they
# go into a certain directory.
dirmessage_enable=YES
#
# Activate logging of uploads/downloads.
xferlog_enable=YES
#
# Make sure PORT transfer connections originate from port 20 (ftp-data).
connect_from_port_20=YES
#
# If you want, you can arrange for uploaded anonymous files to be owned by
# a different user. Note! Using "root" for uploaded files is not
# recommended!
#chown_uploads=YES
#chown_username=whoever
#
# You may override where the log file goes if you like. The default is shown
# below.
#xferlog_file=/var/log/vsftpd.log
#
# If you want, you can have your log file in standard ftpd xferlog format
xferlog_std_format=YES
#
# You may change the default value for timing out an idle session.
#idle_session_timeout=600
#
# You may change the default value for timing out a data connection.
#data_connection_timeout=120
#
# It is recommended that you define on your system a unique user which the
# ftp server can use as a totally isolated and unprivileged user.
#nopriv_user=ftpsecure
#
# Enable this and the server will recognise asynchronous ABOR requests. Not
# recommended for security (the code is non-trivial). Not enabling it,
# however, may confuse older FTP clients.
#async_abor_enable=YES
#
# By default the server will pretend to allow ASCII mode but in fact ignore
# the request. Turn on the below options to have the server actually do ASCII
# mangling on files when in ASCII mode.
# Beware that on some FTP servers, ASCII support allows a denial of service
# attack (DoS) via the command "SIZE /big/file" in ASCII mode. vsftpd
# predicted this attack and has always been safe, reporting the size of the
# raw file.
# ASCII mangling is a horrible feature of the protocol.
#ascii_upload_enable=YES
#ascii_download_enable=YES
#
# You may fully customise the login banner string:
#ftpd_banner=Welcome to blah FTP service.
#
# You may specify a file of disallowed anonymous e-mail addresses. Apparently
# useful for combatting certain DoS attacks.
#deny_email_enable=YES
# (default follows)
#banned_email_file=/etc/vsftpd/banned_emails
#
# You may specify an explicit list of local users to chroot() to their home
# directory. If chroot_local_user is YES, then this list becomes a list of
# users to NOT chroot().
#chroot_list_enable=YES
# (default follows)
#chroot_list_file=/etc/vsftpd/chroot_list
#
# You may activate the "-R" option to the builtin ls. This is disabled by
# default to avoid remote users being able to cause excessive I/O on large
# sites. However, some broken FTP clients such as "ncftp" and "mirror" assume
# the presence of the "-R" option, so there is a strong case for enabling it.
#ls_recurse_enable=YES
#
# When "listen" directive is enabled, vsftpd runs in standalone mode and 
# listens on IPv4 sockets. This directive cannot be used in conjunction 
# with the listen_ipv6 directive.
listen=YES
#
# This directive enables listening on IPv6 sockets. To listen on IPv4 and IPv6
# sockets, you must run two copies of vsftpd whith two configuration files.
# Make sure, that one of the listen options is commented !!
#listen_ipv6=YES

pam_service_name=vsftpd
userlist_enable=YES
tcp_wrappers=YES

[root@epsilon vsftpd]# cat ftpusers 
# Users that are not allowed to login via ftp
root
bin
daemon
adm
lp
sync
shutdown
halt
mail
news
uucp
operator
games
nobody

[root@epsilon vsftpd]# cat user_list 
# vsftpd userlist
# If userlist_deny=NO, only allow users in this file
# If userlist_deny=YES (default), never allow users in this file, and
# do not even prompt for a password.
# Note that the default vsftpd pam config also checks /etc/vsftpd/ftpusers
# for users that are denied.
root
bin
daemon
adm
lp
sync
shutdown
halt
mail
news
uucp
operator
games
nobody

I'd like to get this problem sorted. I can use SFTP but that's considerably slower than FTP because of the extra encryption layer.

Any help would be appreciated.

-------------
Cuvou.com | My personal homepage
Project Fearless | My web blog

 

[thedaver]

Are you running an IPTABLES firewall?

iptables -L


There is a module normally needed called something like ipt_conn_track that is required to support ftp pasv mode. If not enabled, you'll have problems.

Similarly, a firewall may have blocked certain ports

D.E.R. Management - IT Project Management Consulting

http://www.dermanagement.com/

 

[Kirsle]

[root@epsilon ~]# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Running 'service iptables stop' didn't change anything with the FTP daemons.

My iptables config:

[root@epsilon sysconfig]# cat iptables-config 
# Load additional iptables modules (nat helpers)
#   Default: -none-
# Space separated list of nat helpers (e.g. 'ip_nat_ftp ip_nat_irc'), which
# are loaded after the firewall rules are applied. Options for the helpers are
# stored in /etc/modprobe.conf.
IPTABLES_MODULES="ip_conntrack_netbios_ns ip_conntrack_ftp"

# Unload modules on restart and stop
#   Value: yes|no,  default: yes
# This option has to be 'yes' to get to a sane state for a firewall
# restart or stop. Only set to 'no' if there are problems unloading netfilter
# modules.
IPTABLES_MODULES_UNLOAD="yes"

# Save current firewall rules on stop.
#   Value: yes|no,  default: no
# Saves all firewall rules to /etc/sysconfig/iptables if firewall gets stopped
# (e.g. on system shutdown).
IPTABLES_SAVE_ON_STOP="no"

# Save current firewall rules on restart.
#   Value: yes|no,  default: no
# Saves all firewall rules to /etc/sysconfig/iptables if firewall gets
# restarted.
IPTABLES_SAVE_ON_RESTART="no"

# Save (and restore) rule and chain counter.
#   Value: yes|no,  default: no
# Save counters for rules and chains to /etc/sysconfig/iptables if
# 'service iptables save' is called or on stop or restart if SAVE_ON_STOP or
# SAVE_ON_RESTART is enabled.
IPTABLES_SAVE_COUNTER="no"

# Numeric status output
#   Value: yes|no,  default: yes
# Print IP addresses and port numbers in numeric format in the status output.
IPTABLES_STATUS_NUMERIC="yes"

# Verbose status output
#   Value: yes|no,  default: yes
# Print info about the number of packets and bytes plus the "input-" and
# "outputdevice" in the status output.
IPTABLES_STATUS_VERBOSE="no"

# Status output with numbered lines
#   Value: yes|no,  default: yes
# Print a counter/number for every rule in the status output.
IPTABLES_STATUS_LINENUMBERS="yes"

-------------
Cuvou.com | My personal homepage
Project Fearless | My web blog