A simple tutorial on the use of vsftpd under CentOS 6.3

A simple tutorial on the use of vsftpd under CentOS 6.3

1, the basic knowledge about VSFTPD

(1) what is vsftpd. Reference Baidu Encyclopedia, http://baike.baidu.com/view/1806035.htm

(2) 3 Identities of FTP Users: Entity users (real user), visitors (guest), and anonymous logins (anonymous)

A. Entity users (real user): Usually on the Linux system users, but also FTP users, login FTP requires a password

B. Guest (guest): Not Linux system users, but FTP users, login FTP requires a password

C. Anonymous login (anonymous): Not the Linux system users, but FTP users, logon FTP does not require a password

2. Install VSFTPD

[Root@localhost ~]# Yum Install vsftpd

3. Start VSFTPD Service

[root@localhost ~]# Service vsftpd start
starting vsftpd for vsftpd:                                [  OK  ]
[root@localhost ~]# Service VSFTPD status
vsftpd (PID 30196) is running ...

Open ftp://host IP in Chrome, the network address defaults to the/VAR/FTP directory, as follows

4, VSFTPD software organization

/etc/vsftpd/vsftpd.conf	Primary configuration file
/usr/sbin/vsftpd	VSFTPD executable file
/etc/rc.d/init.d/vsftpd	Startup script
/etc/pam.d/vsftpd	Pam Certified Files
/etc/vsftpd/ftpusers	Prohibit the use of VSFTPD user list files
/etc/vsftpd/user_list	Prohibit or allow use of VSFTPD list of users
/var/ftp	Anonymous user home Directory
/var/ftp/pub	Download directory for anonymous users

5, analysis and modification of/etc/vsftpd/vsftpd.conf documents

(1) Backup vsftpd.conf files First

[Root@localhost ~]# Cp/etc/vsftpd/vsftpd.conf/etc/vsftpd/vsftpd.conf.backup

(2) View the configuration instructions for the VSFTPD version and vsftpd.conf file

[Root@localhost ~]# vsftpd-v
vsftpd:version 2.2.2
[root@localhost ~]# man vsftpd.conf

(3) configuration of default vsftpd.conf files (extra annotations removed)

[Root@localhost ~]# cat-n/etc/vsftpd/vsftpd.conf
     1	anonymous_enable=yes
     2	local_enable=yes
     3	write_enable=yes
     4	local_umask=022
     5	dirmessage_enable=yes
     6	xferlog_enable= YES
     7	connect_from_port_20=yes
     8	xferlog_std_format=yes
     9	listen=yes
    10	pam_service_name=vsftpd	userlist_enable=yes	tcp_wrappers=yes
[ Root@localhost ~]#

The above default configuration implements the following features:

A. You can log in using this anonymous account or other entity account (/ETC/PASSWD) anonymous

B. Anonymous's default directory is/var/ftp, and no upload permission has been chroot.

C. default directory reference/etc/passwd for entity users, not chroot, to any directory that has permission to enter

D. Any account that exists within/etc/vsftpd/ftpusers cannot be used VSFTPD

E. Available/etc/host. {Allow|deny} as the underlying firewall

F. When the client has any upload/download information, the information is recorded in the/var/log/vsftpd.log

G. Active connection Port is 20

H. Use GMT (GMT)

(Refer to Brother Bird's private dish ^_^)

(4) My personal modifications (on the default basis), as follows

[Root@localhost ~]# vi/etc/vsftpd/vsftpd.conf # The default settings created by VSFTPD Anonymous_enable=yes local_enable =yes write_enable=yes local_umask=002 dirmessage_enable=yes xferlog_enable=yes connect_from_port_20=yes Format=yes listen=yes pam_service_name=vsftpd userlist_enable=yes tcp_wrappers=yes #---Added by Wesley---# with local t IME Use_localtime=yes # Welcome Information Banner_file=/etc/vsftpd/welcome.txt # Enable chroot and locate chroot_list F Ile Chroot_list_enable=yes Chroot_list_file=/etc/vsftpd/chroot_list # make all real users chroot and let users in Chroot_ List not is chroot # If comment, the users in Chroot_list'll be chroot (It's tricky!) Chroot_local_user=yes # Defeine maximum clients to use FTP max_clients=10 # Define Maximum connections per IP address max_per_ip=5 # relocate RE Al users ' FTP homes to specific folders # By default, real users ' ftp homes is/home/<username> user_config_dir=/etc /vsftpd/userhomes #---End--- 

(a) Use_localtime=yes: Use local time.

(b) Chroot_list_enable=yes: Enable chroot, user login will lock its FTP home directory, cannot switch to another directory.

(c) Chroot_list_file=/etc/vsftpd/chroot_list: When there is only chroot_local_user=no (or no such line), the user in the Chroot_list file (which needs to be created manually), is chroot, user login will lock its FTP home directory, while Chroot_local_user=yes, in Chroot_list file users, is not chroot, users can switch to any directory after login.

(d) When Chroot_local_user=yes:yes or no, triggers the user in chroot_list to allow or disallow chroot.

(e) max_clients=10: Limit the maximum number of FTP connections to 10

(f) Max_per_ip=5: Limit the use of up to 5 FTP connections per IP

(g) User_config_dir=/etc/vsftpd/userhomes, a custom user configuration directory that holds files named after the user name of each entity user (real users), such as/etc/vsftpd/ Userhomes directory to create a test file, of course, the test user is there, in the test file to write a row of local_root=/var/ftp/pub, then test user logon to FTP, the FTP home directory automatically positioned to/var/ftp/pub , rather than the original/home/test.

(h) local_umask=002: The Umask value is used when the FTP user creates a file or folder. This is more than the default configuration, which increases the group user write permissions.

Resources:

1, http://blog.csdn.net/kofterry/article/details/4277267

2, http://os.51cto.com/art/201004/192447.htm

3, http://tanjunjie.blog.51cto.com/6988/774256

4, http://desert3.iteye.com/blog/1685734

5, http://www.cnblogs.com/redhatlinux/archive/2012/04/18/2455737.html

6, http://crazyidea.iteye.com/blog/1207952

7, Http://book.51cto.com/art/201005/199774.htm

8, "Brother Bird's Linux private dish: Server Erection Chapter (second edition)", P631