Enable TELNET in UBUNTU

1. sudoapt-getinstallxinetdtelnetd2. after the installation is successful, the system prompts sudovi/etc/inetd. conf and add the following line telnetstreamtcpnowaittelnetd/usr/sbin/tcpd/usr/sbin/in. telnetd3 ....

 

1. sudo apt-get install xinetd telnetd

2. after the installation is successful, the system will prompt accordingly,

 

Sudo vi/etc/inetd. conf and add the following line

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

3. add the following content to sudo vi/etc/xinetd. conf:

# Simple configuration file for xinetd

#

# Some ULTS ults, and include/etc/xinetd. d/

 

 

ULTS

{

 

 

# 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. d

4. add the following content to sudo vi/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

}

5. restart the machine or restart the network service sudo/etc/init. d/xinetd restart

6. 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. detailed 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 intranet segments are 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. {10, 26}

# The above three lines set stricter external restrictions on www.2cto.com

Instance = 10

Umask = 022

Nice = 10

Flags = REUSE

Socket_type = stream

Wait = no

User = root

# Server =/usr/sbin/telnetd

Server =/usr/sbin/in. telnetd

Log_on_failure + = USERID

}

9. add the firewall iptables:

To enable telnet for the IP address range 192.168.0.0/24 and IP address 61. xxx, 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 -- dport 23-j ACCEPT

/Sbin/iptables-a input-p tcp-I eth0 -- dport 23-j DROP

 

 

10. add a firewall/etc/hosts. allow (deny) mechanism:

The CIDR block 192.168.0.0/24 is enabled, but if you only want ~ Enter 192.168.0.5 and you can set it as follows:

 

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

From hanxuedog