Install and configure telnet in ubuntu

Install and configure telnet in ubuntu 1. after sudo apt-get install xinetd telnetd2. the system prompts sudo vi/etc/inetd. conf and add the following line to telnet stream tcp nowait telnetd/usr/sbin/tcpd/usr/sbin/in. telnetd3. sudo vi/etc/xinetd. conf and add the following content: # Simple configuration file for xinetd # Some 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 info instances = 60 log_type = SYSLOG authpriv log_on_success = host pid log_on_failure = HOST cps = 25 30} includedir/etc/xinetd. d4. sudo vi/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 = no Flags = REUSE socket_type = stream wait = no user = root server =/usr/sbin/in. telnetd log_on_failure = USERID} 5. restart the machine or restart the network service sudo/etc/init. d/xinetd restart6. use the TELNET client to remotely log on to non-root users. 7. log on to mv/etc/securetty. bak as root. You can also modify the/etc/pam. d/login file. Just comment out the following line. # Auth required lib/security/pam_securetty.so 8. specific configuration:/etc/xinetd. d/telnet service telnet {disable = no bind = 192.168.1.2 only_from = 192.168.1.0/24 # the above two lines show that only the Intranet segment is provided! Instance = UNLIMITED Nice = 0 Flags = REUSE socket_type = stream wait = no user = root # server =/usr/sbin/telnetd server =/usr/sbin/in. telnetd server_args =-a none log_on_failure = USERID} service telnet {disable = no bind = 140.116.142.196 only_from = 140.116.0.0/16 no_access = 140.116.32. {} # the above three rows set more strict external restrictions instance = 10 umask = 022 nice = 10 flags = REUSE socket_type = stream wait = no user = root # server =/u Sr/sbin/telnetd server =/usr/sbin/in. telnetd log_on_failure = USERID} 9. add firewall iptables: If you want to address the network segment 192.168.0.0/24 and 61. xxx. xxx. the IP address xxx is available for telnet. You can add the following rules: /sbin/iptables-a input-p tcp-I eth0-s 192.168.0.0/24 -- dport 23-j ACCEPT/sbin/iptables-a input-p tcp-I eth0-s 61. xxx. xxx. xxx -- dport 23-j ACCEPT/sbin/iptables-a input-p tcp-I eth0 -- dport 23-j DROP10. add firewall/etc/hosts. allow (deny) mechanism: above The CIDR Block 192.168.0.0/24 is opened, but if you only want ~ Enter 192.168.0.5. You can set vi/etc/hosts. allow in. telnetd: 192.168.0.1, 192.168.0.2, 192.168.0.3, 192.168.0.4, 192.168.0.5: allow