[리눅스마스터 1급 실기] FTP 서버 설정 (vsftpd)

FTP 서버 설정 (vsftpd)

FTP(File Transfer Protocol)

• TCP/IP 프로토콜 기반으로 서버와 클라이언트 사이에 파일을 주고 받기 위한 프로토콜
• FTP 를 사용하기 위해서는
  • FTP 서버를 구축해야 한다.
  • 서버에 접속하기 위한 계정(아이디 및 패스워드)이 필요하다.
    • 일반적인 FTP 서버는 서버에 등록된 계정만 이용 가능하다.
    • 공개 소프트웨어를 공유하는 서버에서는 익명의 계정(anonymous)을 이용해서 파일을 다운로드 할 수 있다.

• 리눅스에서 사용하는 대표적인 FTP 서버 프로그램
  • Wu-ftpd
    • 유닉스에서 사용되던 프로그램
    • 2000년대 초반까지 리눅스 배포판에 탑재되었으나 현재는 개발이 중단되었다.
  • Proftpd
    • 리눅스 및 유닉스 계열 뿐만 아니라 윈도우까지 지원하는 공개 소프트웨어
    • Wu-ftpd에 비해 기능이 많아지고, 보안성이 강화되었다.
    • 환경 설정 방법이 아파치 웹 서버 파일 과 유사하다.
    • 현재 vsftpd와 함께 가장 많이 사용되는 FTP 서버 프로그램
  • vsftpd
    • Very Secure FTP Daemon
    • 간결하고 안전하며 처리 속도도 매우 빠른 프로그램
    • 리눅스 및 유닉스 계열에서 사용할 수 있다.
    • RHEL, Fedora, CentOS, Ubuntu, Slackware 등의 배포판에 기본적으로 포함되어 있다.
    • 환경 설정 시 YES/NO로 설정하도록 되어 있다.
    • 보안 관련 점검을 많이 한다.
      • 특히 anonymous 계정에 대한 검사를 많이 하는데, anonymous 관련 디렉터리의 퍼미션이 777로 설정되어 있으면 로그인을 막는다.

 

vsftpd 서버 설정

(1) vsftpd 관련 주요 파일

• /etc/vsftpd/vsftpd.conf : vsftpd의 환경 설정 파일
• /etc/pam.d/vsftpd : vsftpd의 PAM 관련 설정 파일
• /etc/vsftpd/ftpusers
  • PAM 관련 설정 파일인 /etc/pam.d/vsftpd 에 사용되는 파일
  • 기본 설정이 접근 거부될 사용자 목록으로 이용된다.
• /etc/vsftpd/user_list
  • vsftpd를 이용하는 사용자 목록 파일
  • 허가 또는 거부 목록 파일로 사용할 수 있다.
  • 기본 설정이 userlist_deny=YES 여서 거부 목록 파일로 사용된다.
• /etc/logrotate.d/vsftpd : vsftpd의 로그 로테이트 관련 파일

 

(2) vsftpd.conf 파일 분석

# cat /etc/vsftpd/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.
# When SELinux is enforcing check for SE bool ftp_home_dir
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.
# When SELinux is enforcing check for SE bool allow_ftpd_anon_write, allow_ftpd_full_access
#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/xferlog
#
# 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. The vsftpd.conf(5) man page explains
# the behaviour when these options are disabled.
# 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().
# (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
#
# 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=NO
#
# 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.
# Make sure, that one of the listen options is commented !!
listen_ipv6=YES
 
pam_service_name=vsftpd
userlist_enable=YES
tcp_wrappers=YES

 

항목 1

anonymous_enable=YES

• 익명 계정의 허가 유무 지정
• 기본 설정 : 사용 가능

 

항목 2

local_enable=YES

• 로컬 사용자, 즉 일반 계정 사용자의 허가 유무 지정
• 기본 설정 : 사용 가능
• 주석 처리나 NO로 지정하면 익명 사용자만 가능하다.

 

항목 3

write_enable=YES

• 쓰기가 가능할 것인지를 지정하는 항목
• 주석 처리하게 되면 파일이나 디렉터리 생성이 불가능하다.

 

항목 4

local_umask=022

• 디렉터리나 파일 생성 시 퍼미션 값을 지정한다.

 

항목 5

anon_upload_enable=YES

• 익명의 사용자들도 업로드가 가능하도록 지정한다.
• 기본 설정 : 주석 처리 (익명의 사용자는 다운로드만 가능)

 

항목 6

anon_mkdir_write_enable=YES

• 익명의 사용자들이 디렉터리를 만들 수 있도록 하는 설정
• 기본 설정 : 주석 처리 (디렉터리 생성 불가능)

 

항목 7

dirmessage_enable=YES

• 접속 시, 메시지를 보여줄 것인지 여부 지정
• 보통 사용자의 홈 디렉터리에 .message 라는 파일에 메시지를 적어 놓으면 접속 시에 나타난다.
• anonymous는 레드햇 계열 리눅스에서 /var/ftp 라는 디렉터리로 연결되므로 이 디렉터리 안에 설정하면 된다.

 

항목 8

xferlog_enable=YES

• 파일 업로드 및 다운로드 관련 로그를 기록할 것인지 지정
• 관련 로그는 /var/log/vsftpd.log 파일에 기록된다.

 

항목 9

connect_from_port_20=YES

• ftp의 데이터 포트인 20번의 사용 유무 지정

 

항목 10

chown_uploads=YES

• anonymous 계정으로 업로드한 파일의 소유권을 변경하도록 할 때 사용
• 이 설정은 chown_username 항목과 같이 사용해야 한다.

 

항목 11

chown_username=whoever

• chown_uploads=YES 와 같이 사용된다.
• 외부에서 anonymous 계정으로 업로드된 파일의 소유권이 이 항목에 지정한 사용자로 변경된다.

 

항목 12

xferlog_file=/var/log/xferlog

• 로그 파일명을 지정하는 옵션
• 기본적으로 주석 처리 되어 있다.
• 해당 파일을 사용할 경우에는 로그 로테이트 관련 파일 도 수정해야 한다.

 

항목 13

xferlog_std_format=YES

• 로그 기록할 때 표준 포맷 사용 여부 지정
• NO : vsftpd에서 사용하는 로그 포맷으로 전환

 

항목 14

idle_session_timeout=600

• 기본 타임아웃 시간을 지정하는 항목
• 단위 : 초

 

항목 15

data_connection_timeout=120

• 데이터 전송 관련 타임아웃 시간을 지정하는 항목
• 단위 : 초

 

항목 16

ftpd_banner=Welcome to blah FTP service.

• 서버 접속 시에 나타나는 메시지를 지정할 때 사용
• 기본적으로 주석 처리 되어 있다.
  • vsftpd 서버의 버전이 메시지로 나타난다.

 

항목 17

chroot_local_user=YES

• 접속한 사용자의 홈 디렉터리를 최상위 디렉터리로 지정
• 이 지시자를 사용하면 모든 접속자에게 적용된다.

 

항목 18

chroot_list_enable=YES

• 지정한 사용자의 홈 디렉터리를 최상위 디렉터리로 지정할 때 사용하는 항목
• 다음 지시자인 chroot_list_file 과 같이 쓰인다.

 

항목 19

chroot_list_file=/etc/vsftpd/chroot_list

• chroot_list_enable=YES 지시자와 같이 사용된다.
• 이 파일에 적용할 사용자를 한 줄에 한 명씩 적으면 된다.

 

항목 20

ls_recurse_enable=YES

• FTP 서버 접속 상태에서 ls -R 명령 사용 시, 하위 디렉터리까지 검색 가능 여부 지정

 

항목 21

listen=YSE

• IPv4 기반으로 standalone 모드로 사용할 경우에 지정하는 항목

 

항목 22

listen_ipv6=YES

• IPv6 기반으로 사용할 경우에 지정하는 항목

 

항목 23

pam_service_name=vsftpd

• PAM 서비스의 이름 지정

 

항목 24

userlist_enable=YES

• 사용자가 직접 목록 파일을 작성하여 지정한 사용자들의 접근을 막을 수 있도록 하는 설정
• 추가적으로 userlist_file=파일명 을 지정해야 한다.

 

항목 25

tcp_wrappers=YES

• TCP Wrappers 를 이용하여 접근 제어할 것인지를 지정하는 항목
• /etc/hosts.allow 및 /etc/hosts.deny 파일을 이용한다.

 

항목 26

session_support=YES

• vsftpd 서버에 접속한 내역을 /var/log/wtmp 파일에 기록하여 last 명령으로 확인할 때 설정하는 항목

 

항목 27

max_clients=50

• 최대 접속자를 지정하는 항목

 

항목 28

max_per_ip=3

• 한 IP 주소 당 허용할 접속수를 지정하는 항목

 

항목 29

listen_port = 21

• vsftpd 데몬이 외부 접속 요청에 통신할 포트를 지정하는 항목

 

항목 30

ftp_data_port = 20

• ftp 데이터 전송에 사용할 포트를 지정하는 항목

 

 

개요

• vsftpd 서버 설정 파일의 내용을 채우는 문제가 출제된다.
• 'rpm -qc vsftpd' 명령으로 관련 환경설정 파일인 /etc/vsftpd/vsftpd.conf 를 찾아서 기본 설정 항목을 확인한다.
• 기본 설정 항목에 제시되지 않은 설정은 'man vsftpd.conf' 명령을 사용하여 찾는다.

• 환경설정 파일 찾기

$ rpm -qc vsftpd

/etc/logrotate.d/vsftpd
/etc/pam.d/vsftpd
/etc/vsftpd/ftpusers
/etc/vsftpd/user_list
/etc/vsftpd/vsftpd.conf

 

• 환경설정 파일의 내용 확인하기

$ cat /etc/vsftpd/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.
# When SELinux is enforcing check for SE bool ftp_home_dir
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.
# When SELinux is enforcing check for SE bool allow_ftpd_anon_write, allow_ftpd_full_access
#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/xferlog
#
# 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. The vsftpd.conf(5) man page explains
# the behaviour when these options are disabled.
# 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().
# (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
#
# 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=NO
#
# 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.
# Make sure, that one of the listen options is commented !!
listen_ipv6=YES
 
pam_service_name=vsftpd
userlist_enable=YES
tcp_wrappers=YES

 

• 기본 설정 항목에 제시되지 않은 설정 확인하기

$ man vsftpd.conf

VSFTPD.CONF(5)                             File Formats Manual                             VSFTPD.CONF(5)
 
 
 
NAME
       vsftpd.conf - config file for vsftpd
 
DESCRIPTION
       vsftpd.conf may be used to control various aspects of vsftpd's behaviour. By default, vsftpd looks
       for this file at the location /etc/vsftpd/vsftpd.conf.  However, you may override this by specify‐
       ing a command line argument to vsftpd. The command line argument is the pathname of the configura‐
       tion file for vsftpd. This behaviour is useful because you may wish to use an advanced inetd  such
       as xinetd to launch vsftpd with different configuration files on a per virtual host basis.
 
       Systemd  changes  the  vsftpd daemon start-up. The vsftpd package contains vsftpd-generator script
       generating symbolic links to /var/run/systemd/generator/vsftpd.target.wants directory. The genera‐
       tor  is  called  during  e.  g.  'systemctl --system daemon-reload'. All these symbolic links link
       /usr/lib/systemd/system/vsftpd@.service file.  The vsftpd daemon(s) is/are controlled  by  one  of
       following ways:
 
       1. Single daemon using default /etc/vsftpd/vsftpd.conf configuration file
       # systemctl {start,stop,...} vsftpd[.service]
 
       2. Single daemon using /etc/vsftpd/<config-filename>.conf
       # systemctl {start,stop,...} vsftpd@<config-filename-without-extension>[.service]
 
       3. All instances together
       # systemctl {restart,stop} vsftpd.target
 
       See systemd.unit(5), systemd.target(5) for further details.
 
FORMAT
       The  format  of  vsftpd.conf is very simple. Each line is either a comment or a directive. Comment
       lines start with a # and are ignored. A directive line has the format:
 
       option=value
 
       It is important to note that it is an error to put any space between the option, = and value.
 
       Each setting has a compiled in default which may be modified in the configuration file.
 
 
BOOLEAN OPTIONS
       Below is a list of boolean options. The value for a boolean option may be set to YES or NO.
 
 
       allow_anon_ssl
              Only applies if ssl_enable is active. If set to YES, anonymous users will be allowed to use
              secured SSL connections.
 
              Default: NO
 
       allow_writeable_chroot
              Allow  chroot()'ing  a user to a directory writable by that user. Note that setting this to
              YES is potentially dangerous. For example, if the user creates an 'etc'  directory  in  the
              new  root directory, they could potentially trick the C library into loading a user-created
              configuration file from the /etc/ directory.
 
              Default: NO
 
       better_stou
              Use a better file name generation algorithm for the  STOU  command.  The  default  original
              algorithm  simply adds an increasing number suffix to the file name, which is prone to race
              conditions if multiple uploaders use the STOU command with the same  file  name  simultane‐
              ously,  which  can result in failure of the command. The new algorithm adds a unique random
              six character suffix to the file name, which  works  much  better  in  face  of  concurrent
              uploads.
 
              Default: NO
 
       anon_mkdir_write_enable
              If  set  to  YES, anonymous users will be permitted to create new directories under certain
              conditions. For this to work, the option write_enable must be activated, and the  anonymous
              ftp user must have write permission on the parent directory.
 
              Default: NO
 
       anon_other_write_enable
              If  set  to  YES,  anonymous users will be permitted to perform write operations other than
              upload and create directory, such as deletion and renaming. This is  generally  not  recom‐
              mended but included for completeness.
 
              Default: NO
 
       anon_upload_enable
              If  set to YES, anonymous users will be permitted to upload files under certain conditions.
              For this to work, the option write_enable must be activated, and  the  anonymous  ftp  user
              must  have  write permission on desired upload locations. This setting is also required for
              virtual users to upload; by default, virtual users are treated with anonymous  (i.e.  maxi‐
              mally restricted) privilege.
 
              Default: NO
 
       anon_world_readable_only
              When  enabled, anonymous users will only be allowed to download files which are world read‐
              able. This is recognising that the ftp user may own files, especially in  the  presence  of
              uploads.
 
              Default: YES
 
       anonymous_enable
              Controls  whether anonymous logins are permitted or not. If enabled, both the usernames ftp
              and anonymous are recognised as anonymous logins.
 
              Default: YES
 
       ascii_download_enable
              When enabled, ASCII mode data transfers will be honoured on downloads.  When disabled,  the
              server  will pretend to allow ASCII mode but in fact ignore requests to activate it. So the
              client will think the ASCII mode is active and therefore may  still  translate  any  <CRLF>
              character sequences in the received file. See the following article for a detailed explana‐
              tion of the behaviour: https://access.redhat.com/articles/3250241.
 
              Turn this option on to have the server actually do ASCII mangling on files  when  in  ASCII
              mode.
 
              Default: NO
 
       ascii_upload_enable
              When  enabled,  ASCII  mode data transfers will be honoured on uploads.  When disabled, the
              server will pretend to allow ASCII mode but in fact ignore requests to activate it. So  the
              client  will  think  the ASCII mode is active and will translate native line terminators to
              the standard <CRLF> line terminators for transmission, but  the  server  will  not  do  any
              translation.  See  the  following  article  for  a  detailed  explanation of the behaviour:
              https://access.redhat.com/articles/3250241.
 
              Turn this option on to have the server actually do ASCII mangling on files  when  in  ASCII
              mode.
 
              Default: NO
 
       async_abor_enable
              When  enabled,  a  special  FTP  command  known  as "async ABOR" will be enabled.  Only ill
              advised FTP clients will use this feature. Additionally, this feature is awkward to handle,
              so  it  is disabled by default. Unfortunately, some FTP clients will hang when cancelling a
              transfer unless this feature is available, so you may wish to enable it.
 
              Default: NO
 
       background
              When enabled, and vsftpd is started in "listen" mode, vsftpd will background  the  listener
              process. i.e. control will immediately be returned to the shell which launched vsftpd.
 
              Default: YES
 
       check_shell
              Note! This option only has an effect for non-PAM builds of vsftpd. If disabled, vsftpd will
              not check /etc/shells for a valid user shell for local logins.
 
              Default: YES
 
       chmod_enable
              When enabled, allows use of the SITE CHMOD command. NOTE! This only applies to local users.
              Anonymous users never get to use SITE CHMOD.
 
              Default: YES
 
       chown_uploads
              If  enabled,  all  anonymously  uploaded  files will have the ownership changed to the user
              specified in the setting chown_username.  This is useful from an administrative,  and  per‐
              haps security, standpoint.
 
              Default: NO
 
       chroot_list_enable
              If  activated,  you  may provide a list of local users who are placed in a chroot() jail in
              their home directory upon login. The meaning is slightly different if chroot_local_user  is
              set  to YES. In this case, the list becomes a list of users which are NOT to be placed in a
              chroot() jail.  By default, the file containing this list is  /etc/vsftpd/chroot_list,  but
              you may override this with the chroot_list_file setting.
 
              Default: NO
 
       chroot_local_user
              If  set  to  YES,  local users will be (by default) placed in a chroot() jail in their home
              directory after login.  Warning: This option has security implications, especially  if  the
              users  have upload permission, or shell access. Only enable if you know what you are doing.
              Note that these security implications are not vsftpd specific. They apply to all  FTP  dae‐
              mons which offer to put local users in chroot() jails.
 
              Default: NO
 
       connect_from_port_20
              This  controls  whether  PORT  style  data connections use port 20 (ftp-data) on the server
              machine. For security reasons, some clients may insist that this is the  case.  Conversely,
              disabling this option enables vsftpd to run with slightly less privilege.
 
              Default: NO (but the sample config file enables it)
 
       debug_ssl
              If  true,  OpenSSL  connection  diagnostics  are  dumped to the vsftpd log file.  (Added in
              v2.0.6).
 
              Default: NO
 
       delete_failed_uploads
              If true, any failed upload files are deleted.  (Added in v2.0.7).
 
              Default: NO
 
       deny_email_enable
              If activated, you may provide a list of anonymous password  e-mail  responses  which  cause
              login to be denied. By default, the file containing this list is /etc/vsftpd/banned_emails,
              but you may override this with the banned_email_file setting.
 
              Default: NO
 
       dirlist_enable
              If set to NO, all directory list commands will give permission denied.
 
              Default: YES
 
       dirmessage_enable
              If enabled, users of the FTP server can be shown messages  when  they  first  enter  a  new
              directory.  By default, a directory is scanned for the file .message, but that may be over‐
              ridden with the configuration setting message_file.
 
              Default: NO (but the sample config file enables it)
 
       download_enable
              If set to NO, all download requests will give permission denied.
 
              Default: YES
 
       dual_log_enable
              If enabled, two log files are generated in parallel, going by default  to  /var/log/xferlog
              and /var/log/vsftpd.log.  The former is a wu-ftpd style transfer log, parseable by standard
              tools. The latter is vsftpd's own style log.
 
              Default: NO
 
       force_dot_files
              If activated, files and directories starting with . will be  shown  in  directory  listings
              even  if  the  "a" flag was not used by the client. This override excludes the "." and ".."
              entries.
 
              Default: NO
 
       force_anon_data_ssl
              Only applies if ssl_enable is activated. If activated, all anonymous logins are  forced  to
              use a secure SSL connection in order to send and receive data on data connections.
 
              Default: NO
 
       force_anon_logins_ssl
              Only  applies  if ssl_enable is activated. If activated, all anonymous logins are forced to
              use a secure SSL connection in order to send the password.
 
              Default: NO
 
       force_local_data_ssl
              Only applies if ssl_enable is activated. If activated, all non-anonymous logins are  forced
              to use a secure SSL connection in order to send and receive data on data connections.
 
              Default: YES
 
       force_local_logins_ssl
              Only  applies if ssl_enable is activated. If activated, all non-anonymous logins are forced
              to use a secure SSL connection in order to send the password.
 
              Default: YES
 
       guest_enable
              If enabled, all non-anonymous logins are classed  as  "guest"  logins.  A  guest  login  is
              remapped to the user specified in the guest_username setting.
 
              Default: NO
 
       hide_ids
              If  enabled,  all  user  and  group  information in directory listings will be displayed as
              "ftp".
 
              Default: NO
 
       implicit_ssl
              If enabled, an SSL handshake is the first thing expect on all connections (the FTPS  proto‐
              col).  To  support  explicit  SSL and/or plain text too, a separate vsftpd listener process
              should be run.
 
              Default: NO
 
       listen If enabled, vsftpd will run in standalone mode. This means that vsftpd must not be run from
              an  inetd  of some kind. Instead, the vsftpd executable is run once directly. vsftpd itself
              will then take care of listening for and handling incoming connections.
 
              Default: NO
 
       listen_ipv6
              Like the listen parameter, except vsftpd will listen on an IPv6 socket instead of  an  IPv4
              one.  Note that a socket listening on the IPv6 "any" address (::) will accept both IPv6 and
              IPv4 connections by default. This parameter and the listen parameter  are  mutually  exclu‐
              sive.
 
              Default: NO
 
       local_enable
              Controls  whether  local  logins  are permitted or not. If enabled, normal user accounts in
              /etc/passwd (or wherever your PAM config references) may be used to log in.  This  must  be
              enable for any non-anonymous login to work, including virtual users.
 
              Default: NO
 
       lock_upload_files
              When  enabled, all uploads proceed with a write lock on the upload file. All downloads pro‐
              ceed with a shared read lock on the download file. WARNING!  Before enabling this, be aware
              that malicious readers could starve a writer wanting to e.g. append a file.
 
              Default: YES
 
       log_die
              Log  an error to syslog when some error condition occurs and vsftpd decides to quit. Inter‐
              nally, the error messages given to the functions die(), die2() and bug() are passed to sys‐
              log.  Currently this functionality requires waiting for a short amount of time (1 second is
              used) after logging the message and before exiting. This is a workaround for the  following
              systemd bug: https://github.com/systemd/systemd/issues/2913
 
              Default: NO
 
       log_ftp_protocol
              When  enabled,  all  FTP  requests  and  responses  are  logged, providing the option xfer‐
              log_std_format is not enabled. Useful for debugging.
 
              Default: NO
 
       ls_recurse_enable
              When enabled, this setting will allow the use of "ls -R". This is a  minor  security  risk,
              because a ls -R at the top level of a large site may consume a lot of resources.
 
              Default: NO
 
       mdtm_write
              When  enabled,  this setting will allow MDTM to set file modification times (subject to the
              usual access checks).
 
              Default: YES
 
       no_anon_password
              When enabled, this prevents vsftpd from asking for an anonymous password  -  the  anonymous
              user will log straight in.
 
              Default: NO
 
       no_log_lock
              When  enabled, this prevents vsftpd from taking a file lock when writing to log files. This
              option should generally not be enabled. It exists to workaround operating system bugs  such
              as  the  Solaris  /  Veritas  filesystem  combination  which has been observed to sometimes
              exhibit hangs trying to lock log files.
 
              Default: NO
 
       one_process_model
              If you have a Linux 2.4 kernel, it is possible to use a different security model which only
              uses  one  process  per connection. It is a less pure security model, but gains you perfor‐
              mance. You really don't want to enable this unless you know what you are  doing,  and  your
              site supports huge numbers of simultaneously connected users.
 
              Default: NO
 
       passwd_chroot_enable
              If  enabled,  along with chroot_local_user , then a chroot() jail location may be specified
              on a per-user basis. Each user's jail is  derived  from  their  home  directory  string  in
              /etc/passwd. The occurrence of /./ in the home directory string denotes that the jail is at
              that particular location in the path.
 
              Default: NO
 
       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
 
       pasv_enable
              Set to NO if you want to disallow the PASV method of obtaining a data connection.
 
              Default: YES
 
       pasv_promiscuous
              Set  to YES if you want to disable the PASV security check that ensures the data connection
              originates from the same IP address as the control connection.  Only  enable  if  you  know
              what  you  are doing! The only legitimate use for this is in some form of secure tunnelling
              scheme, or perhaps to facilitate FXP support.
 
              Default: NO
 
       port_enable
              Set to NO if you want to disallow the PORT method of obtaining a data connection.
 
              Default: YES
 
       port_promiscuous
              Set to YES if you want to disable the PORT security check that ensures that  outgoing  data
              connections can only connect to the client. Only enable if you know what you are doing!
 
              Default: NO
 
       require_cert
              If set to yes, all SSL client connections are required to present a client certificate. The
              degree of validation applied to this certificate is controlled by validate_cert  (Added  in
              v2.0.6).
 
              Default: NO
 
       require_ssl_reuse
              If  set  to  yes, all SSL data connections are required to exhibit SSL session reuse (which
              proves that they know the same master secret as the control channel). Although  this  is  a
              secure default, it may break many FTP clients, so you may want to disable it. For a discus‐
              sion        of         the         consequences,         see         http://scarybeastsecu‐
              rity.blogspot.com/2009/02/vsftpd-210-released.html (Added in v2.1.0).
 
              Default: YES
 
       reverse_lookup_enable
              Set  to  YES  if  you want vsftpd to transform the ip address into the hostname, before pam
              authentication. This is useful if you use pam_access including the hostname.  If  you  want
              vsftpd  to  run  on the environment where the reverse lookup for some hostname is available
              and the name server doesn't respond for a while, you should set this to NO to avoid a  per‐
              formance issue.
 
              Default: YES
 
       run_as_launching_user
              Set  to  YES  if  you  want vsftpd to run as the user which launched vsftpd. This is useful
              where root access is not available. MASSIVE WARNING! Do NOT enable this option  unless  you
              totally  know  what  you are doing, as naive use of this option can create massive security
              problems. Specifically, vsftpd does not / cannot use chroot  technology  to  restrict  file
              access  when  this  option is set (even if launched by root). A poor substitute could be to
              use a deny_file setting such as {/*,*..*}, but the reliability of this  cannot  compare  to
              chroot,  and  should  not  be  relied on.  If using this option, many restrictions on other
              options apply. For example, options  requiring  privilege  such  as  non-anonymous  logins,
              upload  ownership changing, connecting from port 20 and listen ports less than 1024 are not
              expected to work. Other options may be impacted.
 
              Default: NO
 
       secure_email_list_enable
              Set to YES if you want only a specified list of e-mail passwords for anonymous logins to be
              accepted.  This is useful as a low-hassle way of restricting access to low-security content
              without needing virtual users. When enabled, anonymous  logins  are  prevented  unless  the
              password  provided  is listed in the file specified by the email_password_file setting. The
              file format is one password  per  line,  no  extra  whitespace.  The  default  filename  is
              /etc/vsftpd/email_passwords.
 
              Default: NO
 
       session_support
              This  controls  whether vsftpd attempts to maintain sessions for logins. If vsftpd is main‐
              taining sessions, it will try and update utmp and wtmp. It will also open a pam_session  if
              using PAM to authenticate, and only close this upon logout. You may wish to disable this if
              you do not need session logging, and you wish to give vsftpd more opportunity to  run  with
              less  processes and / or less privilege. NOTE - utmp and wtmp support is only provided with
              PAM enabled builds.
 
              Default: NO
 
       setproctitle_enable
              If enabled, vsftpd will try and show session status information in the system process list‐
              ing.  In other words, the reported name of the process will change to reflect what a vsftpd
              session is doing (idle, downloading etc). You probably want to leave this off for  security
              purposes.
 
              Default: NO
 
       ssl_enable
              If enabled, and vsftpd was compiled against OpenSSL, vsftpd will support secure connections
              via SSL. This applies to the control connection (including login)  and  also  data  connec‐
              tions. You'll need a client with SSL support too. NOTE!!  Beware enabling this option. Only
              enable it if you need it. vsftpd can make no guarantees about the security of  the  OpenSSL
              libraries.  By  enabling this option, you are declaring that you trust the security of your
              installed OpenSSL library.
 
              Default: NO
 
       ssl_request_cert
              If enabled, vsftpd will request (but not necessarily require; see require_cert) a  certifi‐
              cate  on  incoming  SSL connections. Normally this should not cause any trouble at all, but
              IBM zOS seems to have issues.  (New in v2.0.7).
 
              Default: YES
 
       ssl_sslv2
              Only applies if ssl_enable is activated. If enabled, this option will permit SSL v2  proto‐
              col connections.  TLS v1.2 connections are preferred.
 
              Default: NO
 
       ssl_sslv3
              Only  applies if ssl_enable is activated. If enabled, this option will permit SSL v3 proto‐
              col connections.  TLS v1.2 connections are preferred.
 
              Default: NO
 
       ssl_tlsv1
              Only applies if ssl_enable is activated. If enabled, this option will permit TLS v1  proto‐
              col connections.  TLS v1.2 connections are preferred.
 
              Default: NO
 
       ssl_tlsv1_1
              Only  applies if ssl_enable is activated. If enabled, this option will permit TLS v1.1 pro‐
              tocol connections.  TLS v1.2 connections are preferred.
 
              Default: NO
 
       ssl_tlsv1_2
              Only applies if ssl_enable is activated. If enabled, this option will permit TLS v1.2  pro‐
              tocol connections.  TLS v1.2 connections are preferred.
 
              Default: YES
 
       strict_ssl_read_eof
              If  enabled,  SSL data uploads are required to terminate via SSL, not an EOF on the socket.
              This option is required to be sure that an attacker did not terminate an upload prematurely
              with  a  faked  TCP FIN. Unfortunately, it is not enabled by default because so few clients
              get it right. (New in v2.0.7).
 
              Default: NO
 
       strict_ssl_write_shutdown
              If enabled, SSL data downloads are required to terminate via SSL, not an EOF on the socket.
              This  is  off  by default as I was unable to find a single FTP client that does this. It is
              minor. All it affects is our ability to tell whether the client confirmed full  receipt  of
              the  file. Even without this option, the client is able to check the integrity of the down‐
              load. (New in v2.0.7).
 
              Default: NO
 
       syslog_enable
              If enabled, then any log output which would have gone to /var/log/vsftpd.log  goes  to  the
              system log instead. Logging is done under the FTPD facility.
 
              Default: NO
 
       tcp_wrappers
              If enabled, and vsftpd was compiled with tcp_wrappers support, incoming connections will be
              fed through tcp_wrappers access control. Furthermore, there is a mechanism for per-IP based
              configuration.  If  tcp_wrappers  sets  the VSFTPD_LOAD_CONF environment variable, then the
              vsftpd session will try and load the vsftpd configuration file specified in this variable.
 
              Default: NO
 
       text_userdb_names
              By default, numeric IDs are shown in the user and group fields of directory  listings.  You
              can get textual names by enabling this parameter. It is off by default for performance rea‐
              sons.  Note that textual names are not guaranteed when chroot_local_user is set to YES.
 
              Default: NO
 
       tilde_user_enable
              If enabled, vsftpd will try and resolve pathnames such as ~chris/pics, i.e.  a  tilde  fol‐
              lowed  by  a username. Note that vsftpd will always resolve the pathnames ~ and ~/something
              (in this case the ~ resolves to the initial login directory). Note that  ~user  paths  will
              only resolve if the file /etc/passwd may be found within the _current_ chroot() jail.
 
              Default: NO
 
       use_localtime
              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.
 
              Default: NO
 
       use_sendfile
              An  internal  setting  used for testing the relative benefit of using the sendfile() system
              call on your platform.
 
              Default: YES
 
       userlist_deny
              This option is examined if userlist_enable is activated. If you set  this  setting  to  NO,
              then  users will be denied login unless they are explicitly listed in the file specified by
              userlist_file.  When login is denied, the denial is issued before the user is asked  for  a
              password.
 
              Default: YES
 
       userlist_enable
              If enabled, vsftpd will load a list of usernames, from the filename given by userlist_file.
              If a user tries to log in using a name in this file, they will be denied  before  they  are
              asked  for a password. This may be useful in preventing cleartext passwords being transmit‐
              ted. See also userlist_deny.
 
              Default: NO
 
       validate_cert
              If set to yes, all SSL client certificates received must validate OK.  Self-signed certs do
              not constitute OK validation. (New in v2.0.6).
 
              Default: NO
 
       userlist_log
              This  option  is  examined  if userlist_enable is activated. If enabled, every login denial
              based on the user list will be logged.
 
              Default: NO
 
       virtual_use_local_privs
              If enabled, virtual users will use the same privileges as local users. By default,  virtual
              users  will  use the same privileges as anonymous users, which tends to be more restrictive
              (especially in terms of write access).
 
              Default: NO
 
       write_enable
              This controls whether any FTP commands which change the  filesystem  are  allowed  or  not.
              These commands are: STOR, DELE, RNFR, RNTO, MKD, RMD, APPE and SITE.
 
              Default: NO
 
       xferlog_enable
              If  enabled,  a  log file will be maintained detailling uploads and downloads.  By default,
              this file will be placed at /var/log/vsftpd.log, but this location may be overridden  using
              the configuration setting vsftpd_log_file.
 
              Default: NO (but the sample config file enables it)
 
       xferlog_std_format
              If  enabled,  the  transfer log file will be written in standard xferlog format, as used by
              wu-ftpd. This is useful because you can reuse existing transfer statistics generators.  The
              default  format  is more readable, however. The default location for this style of log file
              is /var/log/xferlog, but you may change it with the setting xferlog_file.
 
              Default: NO
 
       isolate_network
              If enabled, use CLONE_NEWNET to isolate the untrusted processes so that they can't do arbi‐
              trary connect() and instead have to ask the privileged process for sockets ( port_promiscu‐
              ous have to be disabled).
 
              Default: YES
 
       isolate
              If enabled, use CLONE_NEWPID and CLONE_NEWIPC to isolate processes to  their  ipc  and  pid
              namespaces. So separated processes can not interact with each other.
 
              Default: YES
 
       wc_logs_enable
              If  enabled, logs will be treated as wide-character strings and not just ASCII strings when
              filtering out non-printable characters.
 
              Default: NO
 
 
NUMERIC OPTIONS
       Below is a list of numeric options. A numeric option must be set to a non negative integer.  Octal
       numbers  are supported, for convenience of the umask options. To specify an octal number, use 0 as
       the first digit of the number.
 
 
       accept_timeout
              The timeout, in seconds, for a remote client to establish connection with a PASV style data
              connection.
 
              Default: 60
 
       anon_max_rate
              The maximum data transfer rate permitted, in bytes per second, for anonymous clients.
 
              Default: 0 (unlimited)
 
       anon_umask
              The value that the umask for file creation is set to for anonymous users. NOTE! If you want
              to specify octal values, remember the "0" prefix otherwise the value will be treated  as  a
              base 10 integer!
 
              Default: 077
 
       bind_retries
              Maximum number of attempts to find a free listening port in passive mode.
 
              Default: 9
 
       chown_upload_mode
              The file mode to force for chown()ed anonymous uploads. (Added in v2.0.6).
 
              Default: 0600
 
       connect_timeout
              The timeout, in seconds, for a remote client to respond to our PORT style data connection.
 
              Default: 60
 
       data_connection_timeout
              The  timeout,  in  seconds,  which  is roughly the maximum time we permit data transfers to
              stall for with no progress. If the timeout triggers, the remote client is kicked off.
 
              Default: 300
 
       delay_failed_login
              The number of seconds to pause prior to reporting a failed login.
 
              Default: 1
 
       delay_successful_login
              The number of seconds to pause prior to allowing a successful login.
 
              Default: 0
 
       file_open_mode
              The permissions with which uploaded files are created. Umasks are applied on  top  of  this
              value. You may wish to change to 0777 if you want uploaded files to be executable.
 
              Default: 0666
 
       ftp_data_port
              The  port  from  which  PORT  style connections originate (as long as the poorly named con‐
              nect_from_port_20 is enabled).
 
              Default: 20
 
       idle_session_timeout
              The timeout, in seconds, which is the maximum time a remote client may  spend  between  FTP
              commands. If the timeout triggers, the remote client is kicked off.
 
              Default: 300
 
       listen_port
              If  vsftpd  is in standalone mode, this is the port it will listen on for incoming FTP con‐
              nections.
 
              Default: 21
 
       local_max_rate
              The maximum data transfer rate permitted, in bytes  per  second,  for  local  authenticated
              users.
 
              Default: 0 (unlimited)
 
       local_umask
              The  value that the umask for file creation is set to for local users. NOTE! If you want to
              specify octal values, remember the "0" prefix otherwise the value will be treated as a base
              10 integer!
 
              Default: 077
 
       max_clients
              If  vsftpd  is  in standalone mode, this is the maximum number of clients which may be con‐
              nected. Any additional clients connecting will get an error message.  The value 0  switches
              off the limit.
 
              Default: 2000
 
       max_login_fails
              After this many login failures, the session is killed.
 
              Default: 3
 
       max_per_ip
              If  vsftpd  is  in standalone mode, this is the maximum number of clients which may be con‐
              nected from the same source internet address. A client will get an error message if they go
              over this limit. The value 0 switches off the limit.
 
              Default: 50
 
       pasv_max_port
              The maximum port to allocate for PASV style data connections. Can be used to specify a nar‐
              row port range to assist firewalling.
 
              Default: 0 (use any port)
 
       pasv_min_port
              The minimum port to allocate for PASV style data connections. Can be used to specify a nar‐
              row port range to assist firewalling.
 
              Default: 0 (use any port)
 
       trans_chunk_size
              You  probably  don't  want  to change this, but try setting it to something like 8192 for a
              much smoother bandwidth limiter.
 
              Default: 0 (let vsftpd pick a sensible setting)
 
 
STRING OPTIONS
       Below is a list of string options.
 
 
       anon_root
              This option represents a directory which vsftpd will try to change into after an  anonymous
              login. Failure is silently ignored.
 
              Default: (none)
 
       banned_email_file
              This option is the name of a file containing a list of anonymous e-mail passwords which are
              not permitted. This file is consulted if the option deny_email_enable is enabled.
 
              Default: /etc/vsftpd/banned_emails
 
       banner_file
              This option is the name of a file containing text to display when someone connects  to  the
              server. If set, it overrides the banner string provided by the ftpd_banner option.
 
              Default: (none)
 
       ca_certs_file
              This option is the name of a file to load Certificate Authority certs from, for the purpose
              of validating client certs. The loaded certs are also advertised to the  client,  to  cater
              for  TLSv1.0  clients  such  as  the z/OS FTP client.  Regrettably, the default SSL CA cert
              paths are not used, because of vsftpd's  use  of  restricted  filesystem  spaces  (chroot).
              (Added in v2.0.6).
 
              Default: (none)
 
       chown_username
              This  is  the  name  of the user who is given ownership of anonymously uploaded files. This
              option is only relevant if another option, chown_uploads, is set.
 
              Default: root
 
       chroot_list_file
              The option is the name of a file containing a list of local users which will be placed in a
              chroot()  jail  in  their  home  directory.  This  option  is  only  relevant if the option
              chroot_list_enable is enabled. If the option chroot_local_user is enabled,  then  the  list
              file becomes a list of users to NOT place in a chroot() jail.
 
              Default: /etvsftpd.confc/vsftpd.chroot_list
 
       cmds_allowed
              This  options  specifies  a comma separated list of allowed FTP commands (post login. USER,
              PASS and QUIT and others are always allowed pre-login). Other commands are  rejected.  This
              is    a    powerful   method   of   really   locking   down   an   FTP   server.   Example:
              cmds_allowed=PASV,RETR,QUIT
 
              Default: (none)
 
       cmds_denied
              This options specifies a comma separated list of denied FTP  commands  (post  login.  USER,
              PASS,  QUIT and others are always allowed pre-login). If a command appears on both this and
              cmds_allowed then the denial takes precedence. (Added in v2.1.0).
 
              Default: (none)
 
       deny_file
              This option can be used to set a pattern for filenames (and  directory  names  etc.)  which
              should  not be accessible in any way. The affected items are not hidden, but any attempt to
              do anything to them (download, change into directory,  affect  something  within  directory
              etc.) will be denied. This option is very simple, and should not be used for serious access
              control - the filesystem's permissions should be used in preference. However,  this  option
              may  be  useful  in  certain virtual user setups. In particular aware that if a filename is
              accessible by a variety of names (perhaps due to symbolic links or hard links),  then  care
              must  be  taken  to  deny access to all the names.  Access will be denied to items if their
              name contains the string given by hide_file, or if they match the regular expression speci‐
              fied  by hide_file.  Note that vsftpd's regular expression matching code is a simple imple‐
              mentation which is a subset of full regular expression functionality. Because of this,  you
              will  need  to  carefully and exhaustively test any application of this option. And you are
              recommended to use filesystem permissions for any important security policies due to  their
              greater  reliability.  Supported regex syntax is any number of *, ? and unnested {,} opera‐
              tors. Regex matching is only supported on the last component of a path, e.g. a/b/? is  sup‐
              ported but a/?/c is not.  Example: deny_file={*.mp3,*.mov,.private}
 
              Default: (none)
 
       dsa_cert_file
              This  option specifies the location of the DSA certificate to use for SSL encrypted connec‐
              tions.
 
              Default: (none - an RSA certificate suffices)
 
       dsa_private_key_file
              This option specifies the location of the DSA private key to use for SSL encrypted  connec‐
              tions. If this option is not set, the private key is expected to be in the same file as the
              certificate.
 
              Default: (none)
 
       dh_param_file
              This option specifies the location of the custom parameters used for ephemeral Diffie-Hell‐
              man key exchange in SSL.
 
              Default: (none - use built in parameters appropriate for certificate key size)
 
       ecdh_param_file
              This  option  specifies  the  location  of  custom  parameters for ephemeral Elliptic Curve
              Diffie-Hellman (ECDH) key exchange.
 
              Default: (none - use built in parameters, NIST P-256 with OpenSSL 1.0.1  and  automatically
              selected curve based on client preferences with OpenSSL 1.0.2 and later)
 
       email_password_file
              This   option   can   be   used   to   provide   an   alternate   file  for  usage  by  the
              secure_email_list_enable setting.
 
              Default: /etc/vsftpd/email_passwords
 
       ftp_username
              This is the name of the user we use for handling anonymous FTP. The home directory of  this
              user is the root of the anonymous FTP area.
 
              Default: ftp
 
       ftpd_banner
              This  string  option  allows you to override the greeting banner displayed by vsftpd when a
              connection first comes in.
 
              Default: (none - default vsftpd banner is displayed)
 
       guest_username
              See the boolean setting guest_enable for a description of what constitutes a  guest  login.
              This setting is the real username which guest users are mapped to.
 
              Default: ftp
 
       hide_file
              This  option  can  be  used to set a pattern for filenames (and directory names etc.) which
              should be hidden from directory listings. Despite being hidden,  the  files  /  directories
              etc.  are  fully  accessible  to clients who know what names to actually use. Items will be
              hidden if their names contain the string given by hide_file, or if they match  the  regular
              expression specified by hide_file. Note that vsftpd's regular expression matching code is a
              simple implementation which is a subset of  full  regular  expression  functionality.   See
              deny_file   for   details   of   exactly   what   regex   syntax  is  supported.   Example:
              hide_file={*.mp3,.hidden,hide*,h?}
 
              Default: (none)
 
       listen_address
              If vsftpd is in standalone mode, the default listen address (of all local  interfaces)  may
              be overridden by this setting. Provide a numeric IP address.
 
              Default: (none)
 
       listen_address6
              Like listen_address, but specifies a default listen address for the IPv6 listener (which is
              used if listen_ipv6 is set). Format is standard IPv6 address format.
 
              Default: (none)
 
       local_root
              This option represents a directory which vsftpd will try to change into after a local (i.e.
              non-anonymous) login. Failure is silently ignored.
 
              Default: (none)
 
       message_file
              This  option  is the name of the file we look for when a new directory is entered. The con‐
              tents are displayed to the remote user. This option is only relevant if the option  dirmes‐
              sage_enable is enabled.
 
              Default: .message
 
       nopriv_user
              This  is  the  name of the user that is used by vsftpd when it wants to be totally unprivi‐
              leged. Note that this should be a dedicated user, rather than nobody. The user nobody tends
              to be used for rather a lot of important things on most machines.
 
              Default: nobody
 
       pam_service_name
              This string is the name of the PAM service vsftpd will use.
 
              Default: ftp
 
       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)
 
       rsa_cert_file
              This  option specifies the location of the RSA certificate to use for SSL encrypted connec‐
              tions.
 
              Default: /usr/share/ssl/certs/vsftpd.pem
 
       rsa_private_key_file
              This option specifies the location of the RSA private key to use for SSL encrypted  connec‐
              tions. If this option is not set, the private key is expected to be in the same file as the
              certificate.
 
              Default: (none)
 
       secure_chroot_dir
              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.
 
              Default: /usr/share/empty
 
       ssl_ciphers
              This option can be used to select which SSL ciphers vsftpd will  allow  for  encrypted  SSL
              connections.  See  the  ciphers man page for further details. Note that restricting ciphers
              can be a useful security precaution as it  prevents  malicious  remote  parties  forcing  a
              cipher which they have found problems with.
 
              Default: DES-CBC3-SHA
 
       user_config_dir
              This powerful option allows the override of any config option specified in the manual page,
              on a per-user basis. Usage is simple, and is best illustrated with an example. If  you  set
              user_config_dir  to  be  /etc/vsftpd/user_conf  and  then  log on as the user "chris", then
              vsftpd will apply the settings in the file /etc/vsftpd/user_conf/chris for the duration  of
              the  session.  The format of this file is as detailed in this manual page! PLEASE NOTE that
              not all settings are effective on a per-user basis. For example, many settings  only  prior
              to  the  user's  session  being  started.  Examples  of  settings which will not affect any
              behviour on a per-user basis include listen_address, banner_file, max_per_ip,  max_clients,
              xferlog_file, etc.
 
              Default: (none)
 
       user_sub_token
              This option is useful is conjunction with virtual users. It is used to automatically gener‐
              ate a home directory for each virtual user, based on a template. For example, if  the  home
              directory  of  the  real  user  specified  via  guest_username  is /home/virtual/$USER, and
              user_sub_token is set to $USER, then when virtual user fred logs in, he will end  up  (usu‐
              ally  chroot()'ed)  in  the directory /home/virtual/fred.  This option also takes affect if
              local_root contains user_sub_token.
 
              Default: (none)
 
       userlist_file
              This option is the name of the file loaded when the userlist_enable option is active.
 
              Default: /etc/vsftpd/user_list
 
       vsftpd_log_file
              This option is the name of the file to which we write the vsftpd style log file.  This  log
              is  only  written  if  the option xferlog_enable is set, and xferlog_std_format is NOT set.
              Alternatively, it is written if you have set the option dual_log_enable.  One further  com‐
              plication - if you have set syslog_enable, then this file is not written and output is sent
              to the system log instead.
 
              Default: /var/log/vsftpd.log
 
       xferlog_file
              This option is the name of the file to which we write the wu-ftpd style transfer  log.  The
              transfer  log  is  only  written  if  the  option  xferlog_enable  is set, along with xfer‐
              log_std_format.  Alternatively, it is written if you have set the option dual_log_enable.
 
              Default: /var/log/xferlog
 
 
AUTHOR
       scarybeasts@gmail.com
 
 
 
 
                                                                                           VSFTPD.CONF(5)

 

 

문제 해결 전략

• 'man vsftpd.conf' 명령을 사용하여 설정 항목을 확인하면서 문제를 해결한다.

 

문제 유형

① 조건에 맞게 설정 파일에 내용을 추가하는 문제

vsftpd.conf
(  listen_port  ) = 21
(  local_umask  ) = 022
ftp_data_port = (  20  )

# vi /etc/vsftpd/vsftpd.conf
anonymous_enable=(  NO  )
local_enable=(  YES  )
(  data_connection_timeout  )=120
(  chroot_local_user  )=YES

 

TIP) man vsftpd.conf 명령을 사용하여 설정 항목을 확인하면서 문제를 해결한다.