Install and configure the telnet service in SuSE Linux

How to install and configure the telnet service in SuSE Linux

1. Check whether the SuSE Telnet service is installed (Telent-server is not installed by default .)

# Chkconfig-list

The List displays the following information, indicating that the telnet service has been installed.

Xinetd based services:

TELNET: On

If telnet-server is not installed, install the software package in YaST (telnet-server is in Cd2 ).

2. Start the telnet service:

# Chkconfig telnet on

 

3. confirm that the service has been started:

# Chkconfig-list

Xinetd based services:

TELNET: On

When the service is started, it is displayed as on.

4. modify the configuration file ftpusers so that the root user can log on.

# Cd/etc

# Mv securetty. Bak

/Etc # vi ftpusers

Add a comment before the root so that the root user can log on.

# Root

Save and exit.

5. modify the number of Telnet terminals that can be connected simultaneously.

# Cd/etc

# Vi xinetd. conf

Modify the number of instances:

Instances = 150

Save and exit.

6. Restart the service:

#/Etc/init. d/xinetd restart

Shutting down xinetd: Done

Starting Inet services. (xinetd) done

 

To] Configure ftp and Telnet services on SuSE linux10

During the installation and configuration of FTP on SuSE over the past two days, many problems have been encountered. Here is a summary:
I. Installation
SuSE's graphical user interface is very good, so the installation process is relatively simple.
1. Open YaST, software → software management;
2. The software manager that just started using SuSE is very unaccustomed and cannot find the desired information. However, after a while, it is easier to classify it, it also provides more information for users. In filter → package groups, in the tree list below, productivity → networking → FTP, you can also expand the FTP node and select the servers node;
3. Select vsftpd from the software package list on the left, and click the accept button below. A message is displayed, indicating that the disc is inserted;
4. After you insert the required disc, the system will automatically start installation. After installation is complete, you can view all vsftpd-related files on the file list option page below.
Ii. Start the service
After the installation is complete, vsftpd is started as an independent service and cannot be managed by xinetd. The system automatically adds a service named vsftpd to the service list. To start a service, follow these steps:
1. YaST → system services (run level );
2. Select vsftpd in the service list, click Enable at the bottom, start the service, and finish.
Note: vsftpd may not be started when it is started, sometimes because the service on which it depends is not started, such as syslog. Select Syslog and click Enable. If the xinetd service still cannot be started, restart the xinetd service and then start the vsftpd service.
Iii. Problems Encountered
1. Only anonymous users are allowed to log on
Symptom: During the FTP connection, enter the username and the username angel of the local machine. The following message is displayed: 530 This FTP server is anonymous only. Logon Failed.
Cause: After vsftpd is installed, the default value is anonymous FTP server, and only anonymous users are allowed to log on.
Solution: vsftpd has three server modes: anonymous mode, local mode, and virtual user mode. You need to modify the vsftpd configuration to local mode. The configuration file of vsftpd is located in the/etc/directory and named vsftpd. conf. Many experts have analyzed and explained the configuration file in detail on the Internet, and the comments in the file are also detailed. The following describes only the locations to be modified:
Remove the # Before local_enable = yes to make it available, indicating that local users are allowed to log on;
Added the listen_port = 21 configuration item and set the listening port to 21;
This step is optional. Anonymous users are not allowed to log on. Change the value of anonymous_enable = yes to no and set it as needed.
Restart the vsftpd service: Service vsftpd restart. After the instance is started, log on to the local user Angel and its password during the test.
Note: The above test is performed on the local machine (or after logging on Using SSH.
2. Other machines cannot connect to the server
Symptom: After the local machine passes the test, use ftp 192.168.1.8 on another machine (Windows or RedHat) to connect to the server. The Connection closed by remote host or connection timed out prompt is displayed, and the connection fails.
Cause: The SuSE firewall blocks access from external machines to the port used by FTP.
Solution: Open the firewall's restrictions on ports 20 and 21 used by FTP. The steps are as follows:
I> YaST → security and users → firewall;
II> In the left-side Navigation Pane, select allowed services. In addition, even if the FTP server is installed, no FTP service is available in the servces to allow list, however, ssh, HTTP, https, Samba, and so on are all in the column, so use advanced settings. Click the Advanced button in the lower right corner to open the Advanced Settings dialog box;
III> enter 20 21 in TCP ports. Note that the two port numbers are separated by spaces. OK;
IV> next → accept. test again. The connection is successful. Use the angel and its password in the SuSE system to log on.
Note: although some problems are encountered in SuSE, they are still applicable to vsftpd configurations in other operating systems.
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The default installation of SuSE includes the Telnet client, but does not contain the Telnet server. Therefore, you must install and configure the system after installing the system. The procedure is as follows:
I. Installation
SuSE provides a graphical YaST console for easy use.
1. YaST → software management, open the software manager;
2. Select package groups from the filter on the left, select productivity → networking → other from the tree list of package groups, and select Telent-server from the software list displayed on the right, click the accept button below to prompt you to insert the disc;
3. Insert the required CD as instructed on the screen (this is CD4) and the system will automatically start installation.
Ii. Configuration
After the installation is complete, the telnet service is managed by the xinetd service. By default, the telnet service is disabled, so you need to modify its configuration file to open the service. The Telent configuration file is located in the/etc/xinetd. d/directory and is named Telnet. open the file and modify it as follows:
Disable = Yes → disable = No
From the notes in the Telnet file, we can see that the default status is disabled, that is, default: off.
After modification, restart the xinetd service. The restart command is:
Service xinetd restart
After the xinetd service is restarted successfully, the telnet service is also started.
3. Set firewall
After the above steps, although Telent has been enabled, due to the limitations of the SuSE firewall, other machines cannot use Telnet to access the machine, therefore, you must enable the firewall's limit on port 23 used by Telnet. The procedure is as follows:
1. YaST → security and users → firewall. Enable Firewall settings;
2. Select allowed services in the list on the left. Because there is no Telnet service in services to allow, use its advanced settings. Click the advance button and add 23 to TCP ports.
Note that the delimiter between values in TCP ports is a space.
3. Click OK → next → accept.

After the preceding three steps, you can test the telnet service on other machines.