Telnet Server not starting

After installing telnetd and xinetd with command

sudo apt-get install xinetd telnetd

Create file telnet and put in /etc/xinetd.d

sudo nano /etc/xinetd.d/telnet

# 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
}

Restart xinetd service

sudo service xinetd restart

In xinetd.conf you have includedir /etc/xinetd.d and don't need line

telnet stream tcp nowait telnetd /usr/sbin/tcpd /usr/sbin/in.telnetd

erase it.

In telnet file you can add more option like:

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.