Serv-u: Fast build powerful FTP server

Serv-u: Fast build powerful FTP server
The rapid development of the Internet provides people with unprecedented information resources, and more and more people want to have their own online home when they enjoy the new experience brought by the Internet. In today's popular Internet applications, the number of WWW and FTP file transfer is the most popular. This article will combine serv-u this powerful, user-friendly, easy to learn and Easy-to-use FTP server software, detailed description of how in the shortest possible time to establish a complete FTP server. In addition to the specific installation and configuration instructions, the article will also involve some of the use of FTP to understand the relevant knowledge, hope to be able to help the vast number of netizens.


Brief introduction


Serv-u is currently one of the many FTP server software. By using Serv-u, users can set up any PC as an FTP server, so that users or other consumers can use the FTP protocol to connect to the FTP server by using any PC on the same network to duplicate a file or directory
System, move, create, and delete. The FTP protocol mentioned here is specifically used to specify the standards and rules for file transfer between computers, just because there is a special protocol such as FTP, so that people can use different types of computers, different types of operating systems, different types of files to communicate with each other.


Although the current FTP server-side software variety, each have advantages, but serv-u by virtue of its unique function to expose the head. Specifically, Serv-u can provide the following features:

Windows-compliant user interface is friendly and easy to master.


Supports real-time multi-user connections, supports anonymous user access, and ensures PC uptime by limiting the maximum number of user visits at the same time.


Security can be outstanding. Security precautions can be set at both the directory and file levels. can provide different settings for different users, support the group to manage a large number of users. You can grant or deny access to users based on IP.


Support for file upload and download of breakpoints in the process of continuous transmission.


Multiple-homed sites with multiple IP addresses are supported.


can set the ratio of upload and download, hard disk space quota, network use bandwidth, etc., so that the user limited resources can not be consumed by a large number of FTP access users.


Can be run as a system service background.


Can be used to set the user login or exit when the display information, support for the Unix-style external links.


Listed above are just a serv-u of a number of functions, the specific use will be detailed in the next article, here to illustrate the point, serv-u in the maintenance of a comprehensive, powerful foundation, provide a completely easy-to-use interface, you can say that everything in control.

Instructions for use


All of the setup issues that users may encounter during the use of Serv-u can be implemented through the menu options in the Serv-u window. If the user after installing Serv-u, start serv-u, the screen does not show the Serv-u control window, you can right-click in the taskbar system tray serv-u icon (a capital letter "U"), and then select the pop-up menu of the first "show window so that the Serv-u control window will be displayed on the screen.

Setting up an FTP server




The first item "Ftp-server" In the Setup menu in the Serv-u control window is used to set the FTP server overall. The first "FTP port number" in the window that appears after the selection is used to set the port numbers that the FTP server uses, and the FTP server will listen to all the visitors ' information through that port. In general, the FTP server's default port number is 21, but users can change freely according to their circumstances, as long as they can ensure that the port number used is not in conflict with other network applications. The point to note here is that using the server port that the user chooses is a good security precaution, and only the user and other users who know the port number can successfully connect to the server. Therefore, it is recommended that users use their own selected ports when setting up an FTP server, rather than simply using the default values.


The user then needs to set the maximum speed that the server can provide. In general, the user can empty this out, then the server will use all the possible bandwidth to provide services to customers. It is good to be able to provide maximum access to the user, but too many FTP users may eat up all the possible bandwidth, making other network applications almost impossible to implement. Therefore, it is important to have a reasonable control over the maximum bandwidth that the FTP server can occupy.


The next item is to set the maximum number of user visits allowed by the server. This allows users to limit the maximum number of FTP servers that can be accessed at the same time. If the entry is set to 0, the FTP server will deny any user access requirements, and if the item is vacated, Serv-u will not control the number of visitors until all system resources are exhausted. If users want their FTP servers to function properly, it is best to limit the number of visitors to the site. In general, even the older 486 machines, after using Serv-u, can provide access support for more than 20 users at the same time.


The first of a series of complex options after this is "start security features." If the user does not select the item, then anyone can access the FTP server directly through the network, and any files in the server are randomly copied, altered, or even deleted. In addition to those who have a small range of personal networks, do not want each login to repeat the user name, password and other tumultuous procedures, the user must ensure that the option has been selected, that is, the security of the server to start the function.


The next "ENCRYPT passwords" is automatically selected by default. In this way, Serv-u will use the same encryption mechanism as the UNIX operating system to encrypt and save the user's password. If the user does not choose to encrypt the password, all passwords entered by the user will be saved in plaintext in the Serv-u.ini file located in the Serv-u installation directory.


A subsequent entry is used to set whether anonymous access to the user input password is required. By default, the entry is blank so that users who use anonymous accounts to access the FTP server will not be required to enter a password. It is important to note that the detection of anonymous user passwords is very simple, as long as anonymous users enter any string that matches the format of the mail address, Serv-u will not further determine whether the e-mail address that the user entered is real.


The next step is to prevent the go-ahead. If the user chooses this option, Serv-u will adopt a new time billing method that they want to send to the server on a regular basis
command to prevent a timeout operation from being successful.


Subsequent options are used to set whether to delete files that do not have a full upload, if the user does not use the deletion function, then when a user uploads files to the FTP server in the process of error and did not realize the full file upload, Serv-u will be on the hard disk to retain the uploaded content, In order to achieve the upload file breakpoint continued transmission.


Here's what we're going to talk about across FTP attacks. Typically, when a file is transmitted using the FTP protocol, the client first issues a "port" command to the FTP server that contains the user's IP address and the port number that will be used for data transfer. After the server receives the command, it uses the user address information provided by the command to establish a connection with the user. In most cases, there is no problem with the above procedure, but when a client is a malicious user, the FTP server may be connected to other non-client machines by adding specific address information to the port command. Although the malicious user may not have the right to direct access to a particular machine, if the FTP server has access to the machine, then the malicious user, through the FTP server as an intermediary, will still be able to finally achieve the connection to the target server. This is what we refer to as cross server attacks. To prevent this from happening, users can select the "Prevent attacks across FTP servers" option so that Serv-u first verifies that the address information provided by the user is its true address before establishing a connection to any of the visitors. Everything is a two-way thing. We already know that using serv-u can prevent attacks across FTP servers, but we also give up the ability to transfer data between FTP servers and FTP servers. This is because the Serv-u only establishes a connection with those who provide the address that matches the actual address of the address provider, and the user will not be able to remotely control file transfers between two different FTP servers.

The last two options limit the maximum amount of time a user stays on an FTP server and specify the case of files and directory names on the server.


The other related options in this window are described in more detail later.


User account Management




One of the most basic tasks for users to use an FTP server is to add and manage user information. Open the Serv-u User Management window by selecting Users on the SETUP menu. The window can be divided into about two parts. The left window is used to display the users of all currently registered FTP servers. Select one of the users, and their detailed configuration information will be displayed on the right side of the window accordingly. If this is the first time you start Serv-u, only a system default account named "Default" will be displayed.

The following is a detailed description of the entire process of creating a new user account.


First click the NEW button at the far right of the window and enter the user name you want to create in the pop-up window that follows. The user name you enter appears in the User Name column to the right of the window. The user can also modify the name of the account established in this column.


The user can then enter the group name of the user group to which the account will belong or create a new group. The so-called group is the concept of people in order to facilitate the management of a large number of user groups introduced. We can divide a large number of individual users into different groups for unified management. Because users belonging to the same group have some common attributes, such as user password, root directory, etc., so users only need to individually set up individual accounts with special attributes, which greatly simplifies the management and maintenance of user accounts. It is important to note that the special user account "Anonymous" does not belong to any one user group.


In the subsequent password bar, you need to enter the password of the account number, if the user in the server's settings to select the Encryption password option (see above), then the password entered will automatically be stored in encrypted mode. The important point about the password is that only the first 8 characters of the input are valid, hoping to attract the attention of the vast serv-u users. In addition, if the user does not enter the corresponding password when creating the new account number, it does not mean that the user account does not have a password, serv-u will try to find out if the user account belongs to a user group and the user group has a uniform password. If Serv-u does not find the appropriate user group password, it will deny access to that user account. If the user really wants to not specify the password for an account, just enter "<>" in the password of the corresponding account number. An exception to this is the anonymous user account, which does not have a password, and serv-u only requires the user to enter any string that matches the e-mail address format
Can


In the "Home" column, set the FTP user's root directory, which is the home directory that the user automatically resides in after a successful logon. Each user account must have its own root directory, otherwise serv-u will deny access to that user account. Of course, if the account belongs to a group and the user group already has a common root, then the user does not have to repeat the settings for each account in the user group. Users should be aware of the need to use the full path, including the letter letter, when entering the address of the root directory.

In the "Note" column, the user can choose to enter some text for the account number to assist in future reference.


The largest column to the right of the user's window is used to set the access rights of the account, determining which files users can access and how to access them. Serv-u the user's access rights according to the file and directory categories. Specifically, it includes:


Access rights to files:


READ: Allows users to download files;


WRITE: Allows users to upload files, but not the right to make changes to the file, delete, or rename;


APPEND: Allows users to attach to existing files, and users with APPEND permissions automatically have write


Permissions


Delete: Allows the user to make changes to the file, rename it, or delete it. Users who have the Delete permission automatically hold


Have write and append permissions;


EXECUTE: Allows the user to run the executable file through FTP. For example, a user can run DOS or Windows remotely


Program.


Access permissions to the directory:


List: Allows users to obtain a directory listing;


Make: Allows the user to create a new subdirectory under the root directory;


Remove: Allows the user to delete subdirectories under the root directory.


INHERIT: When this option is selected, the access rights set for a directory are automatically owned by all subdirectories in the directory


Inherited.


After you have completed all of the above settings, click on the "STORE" button and the newly created user account will be saved in the FTP server.


The other options in this window will be described in more detail later.


Real-time monitoring




After the user completes the basic configuration of the FTP server, it can provide FTP file transfer service to the outside world. I think a lot of users would like to provide FTP services
In the process of real-time access to their own server to monitor the user, so that on the one hand can not only be aware of the entire service process, on the other hand also
Timely precautions and remedial actions may be taken before unexpected problems occur. In this respect, I believe serv-u can fully meet the needs of everyone.

First, let's take a look at how to implement real-time user monitoring with Serv-u.


Select the USER INFO option on the FILE menu. The top half of the pop-up window will display all users currently connected to the server.
Clicking any user with the mouse will show the user details in the bottom half of the window.


At the bottom right of the window there is a "SPY on user" button, and the window that appears will show a specific user sending to the FTP server and the FTP service
All commands that the service responds to. This window will track all of the commands for the selected user, providing you with an understanding of all the behavior of a particular user during access to the FTP server
A reliable basis.


Under this button there is also a button named "KILL User", if the user discovers a visitor's behavior is suspicious, may be to the FTP server's positive
If the work is harmful, you can immediately disconnect the user by using this button and kick the user out of the FTP server.


It is important to note that while Serv-u can provide real-time user monitoring information, it requires a large portion of the system resources to be consumed. If the user finds
System performance can be significantly reduced, the window to the right of the "FREEZE LIST" button to temporarily freeze the dynamic display of information, thereby releasing valuable
system resources.

Setting up server-side logging




In addition to being able to monitor in real time, Serv-u also provides a powerful logging function that facilitates user record and summary of Serv-u during a period of time.
Operating conditions.


Select "LOGGING" under the "FILE" menu, the pop-up Log Settings window, the user can choose which events to record, and save the record information to
Where.


On the right side of the window, the user can choose to record different events, including system information, security information, and so on, while the user can also set the
The information that is logged is displayed in the main window of the Serv-u, or is saved to a specified file. For consumption of system resources and backup information needs, users are advised to
Log information is saved to the specified file.

One point to note is that the Serv-u logging file is in a uniform format, as follows:


[n] DATE time-(XXXX) message


The first digit, "n", represents the category of information that is logged, respectively:


N=1: System Information (error information, etc.);


N=2: FTP command issued by user;


n=3: File download;


n=4: File upload;


N=5: Security information (user login information, etc.)


N=6: FTP command for server response;


N=7:winsock use records;


N=8:dll File Access record


In addition, the "XXXX" in parentheses is a unique digital ID given to each visiting user by Serv-u.


5. Set Logon and exit information




Careful users may find that when you log in or exit an FTP site, a window often appears, showing some including system settings, welcome access, etc.
of information. So how to implement this function under the serv-u?


First, the user needs to save the information to be displayed to the user in a text file, then select "MESSAGES" in the "SETUP" menu, and the pop-up
window to set it up.


In the down box at the top of the window, the user needs to select the IP address that will use logon and exit information. Because Serv-u supports a single machine with multiple
IP, so the user needs to select the appropriate IP address. In the two options below, enter the text that the user has previously established that contains login and exit information
The address of the piece.

Using external connections


An external connection is one that shows a connection to a file or directory that is located outside the directory under a directory. In the view of the client, the external connection
The file or directory you point to is under the current directory, but in fact they are just virtual pointers to connect. One of the biggest benefits of using an external connection is
is the ability to centralize all of the resources that a visiting user may need into a single directory, so that users can access them through different external connections that are actually located in different
Scattered information about a disk or a different directory.

To take full advantage of the external connectivity features provided by Serv-u, users first need to generate a text file to hold all external connections that might be used. of the file
The specific format is as follows:


LINK NAME | SOURCENAME


"LINK name" is the name of the external connection that is displayed in the user's current directory, and "SOURCENAME" is the disk that the external connection actually points to
or directory.


For example we are in a named "LINK." TXT file is written in the following article:


CD-ROM | F:\


The word "CD-ROM" appears in the user's current directory, and you can access the FTP server's optical drive directly after clicking it.


After you have configured the externally connected text files, select FTP SERVER in the Ftle menu and find the "PRIMARY Fiel" in the pop-up window.
Containing LINK, and enter the full path to the above text file. Under "PRIMARY Fiel containing LINK" There is a "secondary
File containing link, which is used to set up the auxiliary external connection file, can be generated by reference to the above method.

Set upload and download proportions




If users want their own FTP site users not only use their own resources, but also upload some valuable things for everyone to share, you can
To achieve this by using the "Upload and download scale" feature provided by Serv-u.


Users can find features named "u/d ratios" in the "Ftp-server", "Users" and "GROUPS" pop-up windows on the "FILE" menu
button and the Settings window appears after clicking. Users can limit the number of files that can be downloaded by each user of an FTP site after uploading a file. For example, if you would
A user's upload and download ratio is set to 1/3, so the user can download 3 files from the FTP site each time they upload a file.

Serv-u supports the user's upload and the following in the context of a single session or full session, depending on the number of files transferred or the size of the file
Load ratio.


Using Disk quotas




With the increase in the number of users, a very practical question is how to ensure that each user has enough hard disk space available, while preventing FTP
The server swallows the entire machine's hard disk resources. In the same way, Serv-u provides a powerful solution to this problem.


Users can find a feature button named "Quato" in the pop-up window of the "Users" and "GROUPS" options on the "FILE" menu. Click on the
After the Setup window appears, the user can first detect the hard disk space currently used by a user account, and then set up different user accounts according to the specific situation.
Can control the maximum hard disk space, so as to effectively solve the problem of insufficient space on the hard disk.

Grant or deny access based on IP address




Select the IP ACCESS option on the FILE menu and set it in the pop-up window.


Users can set different access rules on the left side of the window, and all current access rules will appear in the list on the right.


SERV-U provides two basic access rules, the access denied rule and the Allow access rule, respectively. Under the "Access denied" rule, all to
Visitors from the IP address entered by the user will be denied access, and users from other IP addresses will be granted access rights. Similarly, if the user chooses the
Allow access rule, all visitors from the IP address entered by the user will be granted access, and users from other IP addresses will not be authorized to access
FTP server.

Through the above functions, users can set different permissions for different IP addresses, so as to effectively protect the FTP server from illegal visitors.


Three Section


Serv-u is a simple, powerful, easy to learn and easy to use FTP server-side software. Believe that the majority of users with the introduction of the above, coupled with personal practice, will be in the shortest possible time to build their own powerful FTP server.