Configure the Telnet server in Ubuntu

1. configure the Telnet server in Ubuntu. First, we will introduce the linux daemon which has a special Daemon (InterNETservicesDaemon). it is used for Internet standard services and is usually started when the system starts. The configuration of inetd can be provided through the command line... configure the Telnet server in Ubuntu. first, we will introduce that the linux Daemon has a special Daemon in Linux, which is used for InterNET standard services and usually started at system startup. The configuration file of inetd can be provided through the command line, which lists the service list provided by inetd. If the configuration file is not provided in the command line, inetd will read its configuration information from the file/etc/inetd. conf. The main task of inetd is to listen to requests for server processes that are not started at system initialization. it listens to requests on TCP or UDP ports associated with the services listed in the configuration file, when a request arrives at these protocol ports, inetd starts the corresponding server process. When a request arrives at the service port managed by inetd, inetd forwards the request to a program named tcpd. Tcpd checks whether the request is allowed based on the configuration file host. {allow, deny. If the request is allowed, the corresponding server program (such as ftpd and telnet) will be started. This mechanism is also called TCP_Wrapper. Xinetd (eXended InterNET services Daemon) provides functions similar to inetd + tcp_wrapper, but is more powerful and secure. In the commercial systems of mainstream Linux publishers such as Hongqi, xinetd has gradually replaced inetd and provided access control, enhanced log and resource management functions, has become the Internet standard Super daemon for Linux systems. Many system services use xinetd, such as FTP, IMAP, POP, and telnet. When all services in/etc/services access the server through their ports, xinetd is used to process the requests, xinetd first checks whether the requester meets the access control rules specified in the configuration file, whether the current access exceeds the specified number of simultaneous access, and other rules specified in the configuration file, after the check is passed, xinetd delivers the request to the corresponding service for processing, and enters the sleep state, waiting for the processing of the next request. 2. install software 1, $ sudo apt-get install xinetd telnetd 2, $ sudo vim/etc/inetd. conf and add the following line: telnet stream tcp nowait telnetd/usr/sbin/tcpd/usr/sbin/in. telnetd 3, $ sudo vim/etc/xinetd. conf and add the following content: # Simple configuration file for xinetd # Some ULTS ults, and include/etc/xinetd. d/defaults {# Please note that you need a log_type line to be able to use log_on_success # and log_on_failure. the default is the following: # log_type = SYSLOG daemon infoinstances = 60log_type = SYSLOG authprivlog_on_success = HOST PIDlog_on_failure = HOSTcps = 25 30} includedir/etc/xinetd. d 4, $ sudo vim/etc/xinetd. d/telnet and add The following content: # default: on # description: The telnet server serves telnet sessions; it uses # unencrypted username/password pairs for authentication. service telnet {disable = noflags = REUSEsocket_type = streamwait = nouser = rootserver =/usr/sbin/in. telnetdlog_on_failure + = USERID} 5. restart the machine or restart the network service $ sudo/etc/init. d/xinetd restart6: test whether the configuration is successful (you can log on to Ubuntu through the telent server) Method 1: Use the TELNET client to log on remotely (putty login tool, etc.) Method 2: in XP dos (that is, start → run → cmd), enter telnet and then open the Ubuntu IP address (for example, open 192.168.7.106)