一.vsftpd說明:
LINUX下實現FTP服務的軟件很多,最常見的有vsftpd,Wu-ftpd和Proftp等.Red Hat Enterprise Linux中默認安裝的是vsftpd.
訪問FTP服務器時需要經過驗證,只有經過了FTP服務器的相關驗證,用戶才能訪問和傳輸文件.vsftpd提供了3種ftp登錄形式:
(1)anonymous(匿名帳號)
使用anonymous是應用廣泛的一種FTP服務器.如果用戶在FTP服務器上沒有帳號,那麼用戶可以以anonymous爲用戶名,以自己的電子郵件地址爲密碼進行登錄.當匿名用戶登錄FTP服務器後,其登錄目錄爲匿名FTP服務器的根目錄/var/ftp.爲了減輕FTP服務器的負載,一般情況下,應關閉匿名帳號的上傳功能.
(2)real(真實帳號)
real也稱爲本地帳號,就是以真實的用戶名和密碼進行登錄,但前提條件是用戶在FTP服務器上擁有自己的帳號.用真實帳號登錄後,其登錄的目錄爲用戶自己的目錄,該目錄在系統建立帳號時系統就自動創建.
(3)guest(虛擬帳號)
如果用戶在FTP服務器上擁有帳號,但此帳號只能用於文件傳輸服務,那麼該帳號就是guest,guest是真實帳號的一種形式,它們的不同之處在於,geust登錄FTP服務器後,不能訪問除宿主目錄以外的內容.
二.FTP相關配置文件說明
其相關配置文件有/etc/vsftpd/vsftpd.conf, /etc/vsftpd.ftpusers, /etc/vsftpd.user_list,在配置FTP服務器時,主要是修改這些文件中的相關語句.
1.vsftpd.conf文件說明
# 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 //是否允許anonymous登錄FTP服務器,默認是允許的.
#
# Uncomment this to allow local users to log in.
local_enable=YES //是否允許本地用戶登錄FTP服務器,默認是允許
#
# Uncomment this to enable any form of FTP write command.
write_enable=YES //是否允許用戶具有在FTP服務器文件中執行寫的權限,默認是允許
#
# 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 //設置本地用戶的文件生成掩碼爲022,默認是077
#
# Uncomment this to allow the anonymous FTP user to upload files. This only
# has an effect if the above global write enable is activated. Also, you will
# obviously need to create a directory writable by the FTP user.
#anon_upload_enable=YES
#
# Uncomment this if you want the anonymous FTP user to be able to create
# new directories.
#anon_mkdir_write_enable=YES //是否允許匿名賬戶在FTP服務器中創建目錄
#
# Activate directory messages - messages given to remote users when they
# go into a certain directory.
dirmessage_enable=YES //激活目錄信息,當遠程用戶更改目錄時,將出現提示信息
#
# Activate logging of uploads/downloads.
xferlog_enable=YES //啓用上傳和下載日誌功能
#
# Make sure PORT transfer connections originate from port 20 (ftp-data).
connect_from_port_20=YES //啓用FTP數據端口的連接請求
#
# If you want, you can arrange for uploaded anonymous files to be owned by
# a different user. Note! Using "root" for uploaded files is not
# recommended!
#chown_uploads=YES
#chown_username=whoever
#
# You may override where the log file goes if you like. The default is shown
# below.
#xferlog_file=/var/log/vsftpd.log //設置日誌文件的文件名和存儲路徑,這是默認的
#
# If you want, you can have your log file in standard ftpd xferlog format
xferlog_std_format=YES//是否使用標準的ftpd xferlog日誌文件格式
#
# You may change the default value for timing out an idle session.
#idle_session_timeout=600 //設置空閒的用戶會話中斷時間,默認是10分鐘
#
# You may change the default value for timing out a data connection.
#data_connection_timeout=120//設置數據連接超時時間,默認是120秒.
#
# It is recommended that you define on your system a unique user which the
# ftp server can use as a totally isolated and unprivileged user.
#nopriv_user=ftpsecure
#
# Enable this and the server will recognise asynchronous ABOR requests. Not
# recommended for security (the code is non-trivial). Not enabling it,
# however, may confuse older FTP clients.
#async_abor_enable=YES
#
# By default the server will pretend to allow ASCII mode but in fact ignore
# the request. Turn on the below options to have the server actually do ASCII
# mangling on files when in ASCII mode.
# Beware that turning on ascii_download_enable enables malicious remote parties
# to consume your I/O resources, by issuing the command "SIZE /big/file" in
# ASCII mode.
# These ASCII options are split into upload and download because you may wish
# to enable ASCII uploads (to prevent uploaded scripts etc. from breaking),
# without the DoS risk of SIZE and ASCII downloads. ASCII mangling should be
# on the client anyway..
#ascii_upload_enable=YES
#ascii_download_enable=YES //是否允許使用ASCII格式來上傳和下載文件
#
# You may fully customise the login banner string:
#ftpd_banner=Welcome to blah FTP service.//在FTP服務器中設置歡迎登錄的信息.
#
# You may specify a file of disallowed anonymous e-mail addresses. Apparently
# useful for combatting certain DoS attacks.
#deny_email_enable=YES
# (default follows)
#banned_email_file=/etc/vsftpd.banned_emails
#
# You may specify an explicit list of local users to chroot() to their home
# directory. If chroot_local_user is YES, then this list becomes a list of
# users to NOT chroot().
#chroot_list_enable=YES //如果希望用戶登錄後不能切換到自己目錄以外的其它目錄,需要設置該項,如果設置chroot_list_enable=YES,那麼只允許/etc/vsftpd.chroot_list中列出的用戶具有該功能.如果希望所有的本地用戶都執行者chroot,可以增加一行:chroot_local_user=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
pam_service_name=vsftpd //設置PAM認證服務的配置文件名稱,該文件存放在/etc/pam.d/目錄下.
userlist_enable=YES //用戶列表中的用戶是否允許登錄FTP服務器,默認是不允許
#enable for standalone mode
listen=YES //使vsftpd 處於獨立啓動模式
tcp_wrappers=YES //使用tcp_wrqppers作爲主機訪問控制方式
2.vsftpd.ftpusers文件說明
這個文件是用來記錄"不允許"登錄到FTP服務器的用戶,通常是一些系統默認的用戶.
下面是該文件中默認的不允許登錄的名單:
# Users that are not allowed to login via ftp
root //默認情況下,root和它以下的用戶是不允許登錄FTP服務器的.可以將不允許登錄的用戶添加到這裏來.但切記每個用戶都要單獨佔用一行.
bin
daemon
adm
lp
sync
shutdown
halt
news
uucp
operator
games
nobody
3.vsftpd.user_list文件說明
其實它的內容跟上面那個文件內容一樣,只是在系統對文件vsftpd.conf 進行檢測時,會檢測到"userlist_deny=YES",因此這個文件必須存在.下面是這個文件的內容.
# vsftpd userlist
# If userlist_deny=NO, only allow users in this file
# If userlist_deny=YES (default), never allow users in this file, and
# do not even prompt for a password.
# Note that the default vsftpd pam config also checks /etc/vsftpd.ftpusers
# for users that are denied.
root
bin
daemon
adm
lp
sync
shutdown
halt
news
uucp
operator
games
nobody
