Configuring Lightsail bitnami vsftpd passive

Question

I've spent a really long time on this and I had it working last night. Came to work this morning and it has stopped working (I am the only IT support and no changes were made by me).

I have configured my firewall on aws as in the below image.

firewall aws config image

The server is a bitnami/ubuntu server hosted by aws.

I have configured the vsftpd.conf as below

# Example config file /etc/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.
#
#
# Run standalone?  vsftpd can run either from an inetd or as a standalone
# daemon started from an initscript.
listen=NO
#Passive Settings
#listen=yes
#
# This directive enables listening on IPv6 sockets. By default, listening
# on the IPv6 "any" address (::) will accept connections from both IPv6
# and IPv4 clients. It is not necessary to listen on *both* IPv4 and IPv6
# sockets. If you want that (perhaps because you want to listen on specific
# addresses) then you must run two copies of vsftpd with two configuration
# files.
listen_ipv6=YES
#
# Allow anonymous FTP? (Disabled by default).
anonymous_enable=NO
#
# 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
#
# If enabled, vsftpd will display directory listings with the time
# in  your  local  time  zone.  The default is to display GMT. The
# times returned by the MDTM FTP command are also affected by this
# option.
use_localtime=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.
# Note that the default log file location is /var/log/xferlog in this case.
#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 restrict local users to their home directories.  See the FAQ for
# the possible risks in this before using chroot_local_user or
# chroot_list_enable below.
#chroot_local_user=YES
#
# 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().
# (Warning! chroot'ing can be very dangerous. If using chroot, make sure that
# the user does not have write access to the top level directory within the
# chroot)
#chroot_local_user=YES
#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
#
# Customization
#
# Some of vsftpd's settings don't fit the filesystem layout by
# default.
#
# This option should be the name of a directory which is empty.  Also, the
# directory should not be writable by the ftp user. This directory is used
# as a secure chroot() jail at times vsftpd does not require filesystem
# access.
secure_chroot_dir=/var/run/vsftpd/empty
#
# This string is the name of the PAM service vsftpd will use.
pam_service_name=ftp
#
# This option specifies the location of the RSA certificate to use for SSL
# encrypted connections.
rsa_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
rsa_private_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
ssl_enable=NO

#
# Uncomment this to indicate that vsftpd use a utf8 filesystem.
#utf8_filesystem=YES

#user restriction
userlist_file=/etc/vsftpd.userlist
userlist_enable=YES
userlist_deny=NO

# passive/active mode configuration
#port_enable=YES
pasv_enable=YES
pasv_min_port=1200
pasv_max_port=1250
pasv_address=xx.xx.xx.xx
# if pasv_address_resolve=YES, pasv_address should be a name, e.g. ftp.blah.com
#pasv_addr_resolve=YES


seccomp_sandbox=NO

This is what it displays from filezilla:

Status:         Connecting to xx.xx.xx.xx:21...
Status:         Connection established, waiting for welcome message...
Status:         Server does not support non-ASCII characters.
Status:         Logged in
Status:         Retrieving directory listing...
Command:    PWD
Response:   257 "/home/username" is the current directory
Command:    TYPE I
Response:   200 Switching to Binary mode.
Command:    PASV
Error:          Could not read from socket: ECONNRESET - Connection reset by peer
Error:          Disconnected from server
Error:          Failed to retrieve directory listing

Output from the cmd prompt:

[email protected]:~$ sudo ftp localhost
Connected to localhost.
220 (vsFTPd 3.0.3)
Name (localhost:bitnami): username
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
-rw-rw-r--    1 1002     1004          415 Feb 08 15:30 1
226 Directory send OK.
ftp> passive
Passive mode on.
ftp> ls
227 Entering Passive Mode (0,0,0,0,4,224).
150 Here comes the directory listing.
-rw-rw-r--    1 1002     1004          415 Feb 08 15:30 1
226 Directory send OK.
ftp> exit
221 Goodbye.
[email protected]:~$ 

I'd really appreciate any help at all as I am very confused.

It works in active mode but a third party can only ftp in passive mode so I need it for that.

Thanks in advance!

Answer 1

Configure the pasv_address (and pasv_addr_resolve options:

pasv_address

Use this option to override the IP address that vsftpd will advertise in response to the PASV command. Provide a numeric IP address, unless pasv_addr_resolve is enabled, in which case you can provide a hostname which will be DNS resolved for you at startup.

Default: (none - the address is taken from the incoming connected socket)

pasv_addr_resolve

Set to YES if you want to use a hostname (as opposed to IP address) in the pasv_address option.

Default: NO

(From http://vsftpd.beasts.org/vsftpd_conf.html)

I've bugged around with this exact issue last week. Symptoms:

• Using FileZilla in active mode works fine
• Using Automatic or Passive mode results in a timeout or refused connection
• The passive address is printed as 0,0,0,0 in logs

Setting pasv_address to an IP, or to an FQDN while setting passv_addr_resolve to yes solves this problem, as it allows the client to connect to the right destination.