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December 15, 2010
ftp2010-12-15 16:39:33 Read 2 Comments 0 Word Count: I. Introduction
when we need to set up a website available for download function, in addition to using the http connect, but can also provide additional services for users to directly connect ftp download. In fact, ftp is a long-standing service, it is designed to transfer data between two computers in order to avoid too many remote execution. If you want to transfer large files, the terms of the way http connections will take up some websites transfer of resources (for example the number of connections), then we should use ftp the. ftp is a TCP / IP-based applications, it is generally to the ftp service will be embedded in the inetd program is executed.
ftp divided into two parts, one is the server-side program, one is the client. Ftp server on Unix program is very large, different operating systems are not the same built-in version, there are common wu-ftpd, proftpd, Trollftpd, ncftpd and Beroftpd and so on. One of the most commonly used is the most popular wu-ftpd, which is originally developed by the University of Washington wuarchive.wustl.edu, is a consideration of efficiency and stability of the program, which provides open source and academic institutions free of charge.
Second, install and configure
wu-ftpd installation is very easy, most versions of Linux are included in the wu-ftpd the rpm package, you can Linux installation specified load. If you want to compile the source code can also go to ftp://ftp.wu-ftpd.org download the latest version of the source code package.
After installation, you can use ckconfig command to check installed correctly. In the / etc / passwd in ftp user can specify the login directory.
wu-ftpd has the following six main configuration file:
ftpaccess (the main configuration file to control access rights)
ftpconvertions (configuration files compression / decompression conversion)
ftpgroups (the group defined its own set ftp)
ftphosts (setting individual user permissions)
ftpservers (set different IP / DomainName to correspond to a different virtual host)
ftpusers (which account can not be used to set ftp connection)
Here we describe each .
⒈ / etc / ftpaccess (wu-ftpd main configuration file)
class – defined group, use the following:
class < Type> [ ... ...]
groups defined by the class user can connect in, the class can be used to regulate the multi-layered group of users which up from where. There are three major types, real, anonymous one guest. real if not listed in the definition, then the machine in any real average user can not even come up with their own account. anonymous if not defined, it means there is no account of people not to even up. If you have defined guest, then the guest group of people can come up. Also ftp is the user will use up the IP address, you can set their own. Here are some examples:
classallreal, guest, anonymous *
defines a named all of the class, including three kinds of people, all IP connection users (that is, Everyone including)
classlocalreallocalhostloopback
local this class that only real users can connect from the local machine up
classremoteguest, anonymous *
remote included in this class come from anywhere in the guest and anonymous users, but the real user is not
classrmtuserreal! *. example.com
rmtuser This class contains come from the outside (except example.com) real user
autogroup – automatic mapping group, used as follows:
autogroup [... ... ]
When you defined a class that belong to the user, once the connection is up it will be mapped to a corresponding group below, so you can use the Unix file permissions of a group of people do limit.
deny – deny certain address connection, use the following:
deny
ban some machines connect and display . For example:
deny210.62.146 .*: 255.255.255.254/etc/reject.msg
guestgroup – set the visitors group
guestuser – Set the guest account
realgroup – set real group
realuser – set true account
nice – set how much priority given to certain class, usage is as follows:
nice
in Linux, nice values ??is -20 (highest priority) to 19 (last treatment), Here you can specify a negative value to increase the priority class.
defumask – set a class of umask, use the following:
defumask []
umask is set up file permissions of the file mask
tcpwindow – set tcpwindow size
keepalive – set to control whether to use TCPSO_KEEPALIVE break situation
timeout – Set the connection timeout, use the following:
timeoutaccept
accept a connection timeout, default 120 seconds
timeoutconnect < s>
connection establishment timeout, default 120 seconds
timeoutdata
data transfer timeout, default 1200 seconds < br />
timeoutidle
user daze out, default 900 seconds
file-limit – limit of a class can only transfer a few files , usage is as follows:
file-limit [] []
restrict access to files on a class number, include in (upload), out (download) , totalraw behalf of the entire transmission of results, not just data files. For example:
file-limitout20lvfour
limit lvfour this class of users can only download 20 files
byte-limit – limit of a class can only transfer a few bytes, use with file-limit similar
limit-time – limit how long a connection only, usage is as follows:
limit-time {*anonymousguest}
In order to prevent people from hanging on the station for it, you can use this method limit the user on-line time, for example:
limit -timeguest5
allow guest account users can only spend five minutes
limit – limit of a class of several people simultaneously on-line, use the following:
limit
set a class within a certain time period up to a few people on the same line followed when more than the number of connections to display information. For example:
limitall32Any/home/ftp/etc/toomanyuser.msg
all connections at any time restrictions only 32 users, then refuse the connection and display more than Information
limitlevellone5Any2300-0600/home/ftp/etc/toomanyus er.msg
limit levellone users of this class 23:00 to 6:00 at this time only 5 people have connections
noretrieve – set which file is not downloaded
noretrieve [absolute / relative] [class =] … [-][< file name> ...]
absolute or relative path means the file is to use absolute or relative path
allow = retrieve – you can set which files to download
allow [absolute / relative] [class =] … [-][< file name> ...]
loginfails – log error to try to set the number of
even when the user line may be wrong ID or password, this setting allows him to break after a few wrong, prevent people from using brute-force method to guess the password.
private – set the line can perform SITEGROUP / SITEGPASS
When opening SITEGROUP with SITEGPASS command, you can use these two commands to switch to the / etc / ftpgroup of the group. In general we will not use this feature to avoid security vulnerabilities.
greeting – Display Server version information, used as follows:
greeting
When the user login screen displays the server information, full is the pre- set value that contains the version number, and hostname, brief only the hostname, and the terse only “FTPserverready” information.
barnner – set before the user did not enter the Login screen to see information, usage is as follows:
banner
described here User log in when not playing in the ID / Password to appear before the information. Refers to the file path is relative to the true path, not relative to the ftp root directory.
host – set ftp host name
email – the email address specified ftp manager
message – setup information file , usage is as follows:
message { {… …}}
here is the file path relative to the ftp root directory, “Ho time “is when you do what the reaction after the action, there are several options:
login (login)
cwd = (into a directory time)
class name is already defined, allowing your information only which were issued.
and the information content in addition to text files, you can also use the following pre-defined code:
% T (local time)

% F (currently partition the remaining space)
% C (the current directory)
% E (manager of the E-mail)
< br />% R (client host name)
% L (the local host name)
% U (user name)
% M (the same class with me how many users are allowed to connect)
% N (the same class with me how many users are currently connected)
% B (absolute disk limit size, the current partition (in blocks))
% b (preferred disk size limit, the current partition (in blocks))
% Q (currently used blocks) < br />
% I (maximum use of inodes ( 1))
% i (Preferredinodes limit)
% q (currently used indoes)
% H (excessive use of disk space, time limit)
% h (excessive number of files using the time limit)
readme- – inform the user what the README file has been updated
logcommands – record the user used the command, use the following:
logcommands

logtransfers – record user transfer files, use the following:
logtransfers
set which types of users to transfer files to record , contains the inbound (user upload) and outbound (download), for example:
logtransfersanonymous, guestinbound, outbound
logsecurity – record security, usage is as follows: < br />
logsecurity
especially for recording certain types of users on noretrive, notar and other security-related records
logsyslog – recorded system syslog file
alias – set the directory alias is used as follows:
alias
cdpath- – Set the cd change directory search order
compress, tar – set whether to automatically compress, used as follows:
compress [... ...]

tar [... ...]
define who can perform compression and tar
shutdown – notify the user to shut stood
shutdown
If the information file exists, when the file specified after a certain time, it will refuse to connect and disconnect an existing connection, such as the time comes to shut down. This information file format is as follows:

_{daemonaddress – only listen on a specified IP address, use the following:
daemonaddress
When you have a lot of IP, when using this option will cancel any other virtual FTP Host settings. Not set, then listen
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