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.conf. However, you may override this by specifying a command line argument to vsftpd. The command line argument is the pathname of the configuration 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.
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
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 recommended 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. maximally restricted) privilege.
Default: NO
anon_world_readable_only
When enabled, anonymous users will only be allowed to download files which are world readable. 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.
Default: NO
ascii_upload_enable
When enabled, ASCII mode data transfers will be honoured on uploads.
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: NO
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 perhaps 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 daemons 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 overridden 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 protocol). 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: YES
listen_ipv6
Like the listen parameter, except vsftpd will listen on an IPv6 socket instead of an IPv4 one. This parameter and the listen parameter are mutually exclusive.
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 proceed 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_ftp_protocol
When enabled, all FTP requests and responses are logged, providing the option xferlog_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 performance. 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 discussion of the consequences, see http://scarybeastsecurity.blogspot.com/2009/02/vsftpd-210-released.html (Added in v2.1.0).
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 maintaining 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 listing. 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 connections. 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)acertificateonincomingSSLconnections.Normallythis 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 protocol connections. TLS v1 connections are preferred.
Default: NO
ssl_sslv3
Only applies if ssl_enable is activated. If enabled, this option will permit SSL v3 protocol connections. TLS v1 connections are preferred.
Default: NO
ssl_tlsv1
Only applies if ssl_enable is activated. If enabled, this option will permit TLS v1 protocol connections. TLS v1 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 download. (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 reasons.
Default: NO
tilde_user_enable
If enabled, vsftpd will try and resolve pathnames such as ~chris/pics, i.e. a tilde followed 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 transmitted. 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
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
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
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 connect_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 connections.
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 connected. Any additional clients connecting will get an error message.
Default: 0 (unlimited)
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 connected from the same source internet address. A client will get an error message if they go over this limit.
Default: 0 (unlimited)
pasv_max_port
The maximum port to allocate for PASV style data connections. Can be used to specify a narrow 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 narrow 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. 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: /etc/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 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. 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 {,} operators. Regex matching is only supported on the last component of a path, e.g. a/b/? is supported 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 connections.
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 connections. If this option is not set, the private key is expected to be in the same file as the certificate.
Default: (none)
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 contents are displayed to the remote user. This option is only relevant if the option dirmessage_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 unprivileged. 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 connections.
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 connections. 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 generate 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 (usually 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 complication - 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 xferlog_std_format. Alternatively, it is written if you have set the option dual_log_enable.
Default: /var/log/xferlog
----
Source: http://vsftpd.beasts.org/vsftpd_conf.html
Introduction
This tutorial will show you how to set up a TLS/SSL certificate from Let’s Encrypt on a CentOS 7 server running Apache as a web server. Additionally, we will cover how to automate the certificate renewal process using a cron job.
SSL certificates are used within web servers to encrypt the traffic between server and client, providing extra security for users accessing your application. Let’s Encrypt provides an easy way to obtain and install trusted certificates for free.
Prerequisites
In order to complete this guide, you will need:
- A CentOS 7 server with a non-root sudo user, which you can set up by following our Initial Server Setup guide
- At least one domain name configured for your server using A or CNAME records. The exact procedure depends on your domain name registrar or hosting service. If you have purchased a domain name and wish to use it with the DigitalOcean name servers, you can read our guide on setting up your hostname with DigitalOcean to set up the correct records.
For the purpose of this guide, we will install a Let’s Encrypt certificate for the domain
example.com. This will be referenced throughout the guide, but you should substitute it with your own domain while following along.
When you are ready to move on, log into your server using your
sudo account.Step 1 — Installing the Required Software
Before we can install the
certbot Let’s Encrypt client and generate the SSL certificate, we need to install the Apache web server if it is not already available. We will also need to install the mod_ssl module to correctly serve encrypted traffic. Finally, we will need to enable the EPEL repository, which provides additional packages for CentOS, including the certbot package we need.
Enable the EPEL repository first by typing:
- sudo yum install epel-release
Now that you have access to the extra repository, install all of the required packages by typing:
- sudo yum install httpd mod_ssl python-certbot-apache
You should now have all of the packages you need to secure your site.
Step 2 — Configuring Access to Apache
Before we can request a certificate, we need to make sure Apache is running on our server and is accessible to the outside world.
To make sure Apache is up and running, type:
- sudo systemctl start httpd
Verify that Apache is running by checking the status of the service:
- systemctl status httpd
Output
● httpd.service - The Apache HTTP Server
Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled; vendor preset: disabled)
Active: active (running) since Thu 2017-01-05 16:47:06 UTC; 1h 7min ago
Docs: man:httpd(8)
man:apachectl(8)
Main PID: 9531 (httpd)
Status: "Total requests: 10; Current requests/sec: 0; Current traffic: 0 B/sec"
CGroup: /system.slice/httpd.service
├─9531 /usr/sbin/httpd -DFOREGROUND
├─9532 /usr/sbin/httpd -DFOREGROUND
├─9533 /usr/sbin/httpd -DFOREGROUND
├─9534 /usr/sbin/httpd -DFOREGROUND
├─9535 /usr/sbin/httpd -DFOREGROUND
└─9536 /usr/sbin/httpd -DFOREGROUND
Jan 05 16:47:05 centos-512mb-nyc3-01 systemd[1]: Starting The Apache HTTP Server...
Jan 05 16:47:05 centos-512mb-nyc3-01 httpd[9531]: AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using ::1. Set the 'ServerName' directive globally to suppress this message
Jan 05 16:47:06 centos-512mb-nyc3-01 systemd[1]: Started The Apache HTTP Server.
It should say
active towards the top.
Next, make sure port 80 and 443 are open in your firewall. If you are not running a firewall, you can skip ahead.
If you have a firewalld firewall running, you can open these ports by typing:
- sudo firewall-cmd --add-service=http
- sudo firewall-cmd --add-service=https
- sudo firewall-cmd --runtime-to-permanent
If have an iptables firewall running, the commands you need to run are highly dependent on your current rule set. For a basic rule set, you can add HTTP and HTTPS access by typing:
- sudo iptables -I INPUT -p tcp -m tcp --dport 80 -j ACCEPT
- sudo iptables -I INPUT -p tcp -m tcp --dport 443 -j ACCEPT
Check that your site is reachable using curl:
- curl example.com
The HTML for your main page should be displayed. Since the
mod_ssl package configures a self-signed SSL certificate by default, you can check your domain with HTTPS as well if you use the -k flag to allow untrusted certificates:
- curl -k https://example.com
This should allow you to view the same output and verify that the SSL port is open.
Step 3 — Requesting an SSL Certificate from Let's Encrypt
Now that Apache is ready, we can request an SSL certificate for our domain.
Generating the SSL Certificate for Apache using the
certbot Let’s Encrypt client is fairly straightforward. The client will automatically obtain and install a new SSL certificate that is valid for the domains provided as parameters.
If you want to install a single certificate that is valid for multiple domains or subdomains, you can pass them as additional parameters to the command. The first domain name in the list of parameters will be the base domain used by Let’s Encrypt to create the certificate, and for that reason we recommend that you pass the bare top-level domain name as first in the list, followed by any additional subdomains or aliases:
- sudo certbot --apache -d example.com -d www.example.com
For this example, the base domain will be
example.com.
To execute the interactive installation and obtain a certificate that covers only a single domain, run the
certbot command with:
- sudo certbot --apache -d example.com
The
certbot utility can also prompt you for domain information during the certificate request procedure. To use this functionality, call certbot without any domains:
- sudo certbot --apache
You will be presented with a step-by-step guide to customize your certificate options. You will be asked to provide an email address for lost key recovery and notices. If you did not specify your domains on the command line, you will be prompted for that as well. If your Virtual Host files do not specify the domain they serve explicitly using the
ServerName directive, you will be asked to choose the Virtual Host file (the default ssl.conf file should work).
You will also be able to choose between enabling both
http and https access or forcing all requests to redirect to https. For better security, it is recommended to choose the Secure option if you do not have any special need to allow unencrypted connections.
When the installation is successfully finished, you should see a message similar to this:
IMPORTANT NOTES:
- Congratulations! Your certificate and chain have been saved at
/etc/letsencrypt/live/example.com/fullchain.pem. Your cert
will expire on 2016-04-21. To obtain a new version of the
certificate in the future, simply run Let's Encrypt again.
- If you lose your account credentials, you can recover through
e-mails sent to user@example.com.
- Your account credentials have been saved in your Let's Encrypt
configuration directory at /etc/letsencrypt. You should make a
secure backup of this folder now. This configuration directory will
also contain certificates and private keys obtained by Let's
Encrypt so making regular backups of this folder is ideal.
- If you like Let's Encrypt, please consider supporting our work by:
Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate
Donating to EFF: https://eff.org/donate-le
The generated certificate files should be available within a subdirectory named after your base domain in the
/etc/letsencrypt/live directory.
Before we check our SSL certificate, we should modify CentOS's default SSL configuration to make it more secure.
Step 4 — Selecting More Secure SSL Settings for Apache
The default SSL configuration shipped with CentOS's version of Apache is a bit dated and as such, it is vulnerable to some more recent security issues.
To configure more secure SSL-related options, open the
ssl.conf file (or whichever Virtual Host file you selected when prompted during the Let's Encrypt request process):
- sudo nano /etc/httpd/conf.d/ssl.conf
Inside, we should first find the
SSLProtocol and SSLCipherSuite lines and either delete them or comment them out. The configuration we be pasting in a moment will offer more secure settings than the default included with CentOS's Apache:
/etc/httpd/conf.d/ssl.conf
. . .
# SSLProtocol all -SSLv2
. . .
# SSLCipherSuite HIGH:MEDIUM:!aNULL:!MD5:!SEED:!IDEA
Next, to set up Apache SSL more securely, we will be using the recommendations by Remy van Elst on the Cipherli.st site. This site is designed to provide easy-to-consume encryption settings for popular software. You can read more about his decisions regarding the Apache choices here.
Note: The suggested settings on the site linked to above offer strong security. Sometimes, this comes at the cost of greater client compatibility. If you need to support older clients, there is an alternative list that can be accessed by clicking the link on the page labelled "Yes, give me a ciphersuite that works with legacy / old software." That list can be substituted for the items copied below.
The choice of which config you use will depend largely on what you need to support. They both will provide great security.
For our purposes, we can copy the provided settings in their entirety. We will just make two small changes.
Take a moment to read up on HTTP Strict Transport Security, or HSTS, and specifically about the "preload" functionality. Preloading HSTS provides increased security, but can have far reaching consequences if accidentally enabled or enabled incorrectly. In this guide, we will not preload the settings, but you can modify that if you are sure you understand the implications.
The other change we will make is to comment out the
SSLSessionTickets directive since this isn't available in the version of Apache shipped with CentOS 7.
Paste in the settings from the site AFTER the end of the
VirtualHost block:
/etc/httpd/conf.d/ssl.conf
. . .