转：http://ubuntuguide.net/install-and-enable-telnet-server-in-ubuntu-linux
参考：http://auxnet.org/index.php?option=com_content&view=article&id=62:how-to-install-a-turn-on-telnet-service-on-rhel-fedora-centos-ubuntu-freebsd-debian&catid=1:latest-news&Itemid=50
本方法也适用于Debian Linux。
Install and Enable Telnet server in Ubuntu Linux
1.Install telnet use this command in terminal(Applications/Accessories/Terminal):
sudo apt-get install xinetd telnetd
2.Edit /etc/inetd.conf using your favourite file editor with root permission,add this line:
telnet stream tcp nowait telnetd /usr/sbin/tcpd /usr/sbin/in.telnetd
注意：如果inetd.conf不存在，可以手动创建
3.Edit /etc/xinetd.conf,make its content look like following:
# Simple configuration file for xinetd
#
# Some defaults, 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
}
4.You can change telnet port number by edit /etc/services with this line:
telnet 23/tcp
5.If you’re not satisfied with default configuration.Edit etc/xinetd.d/telnet, add following:
# 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
}
add these lines as you like:（以下内容可以不添加）
only_from = 192.168.120.0/24 #Only users in 192.168.120.0 can access to
only_from = .bob.com #allow access from bob.com
no_access = 192.168.120.{101,105} #not allow access from the two IP.
access_times = 8:00-9:00 20:00-21:00 #allow access in the two times
......
6.Use this command to start telnet server:
sudo /etc/init.d/xinetd restart