Linux centos/rhel/scientific install Telnet on Linux 6 & 7

Source: Internet
Author: User

Statement:

Before you install and use Telnet, you need to keep the following points in mind.

Using Telnet in a public network (WAN) is a very bad idea. It transmits log-in data in plaintext format. Clear text is visible to everyone.
If you still need telnet, it is strongly recommended that you only use it inside the LAN.
You can use SSH as a workaround. But be sure not to log in with the root user.


What is Telnet?

Telnet is the protocol used to telnet to a computer over a TCP/IP network. Once a connection is made to the remote computer, it becomes a virtual terminal and allows you to communicate with the remote computer.

In this tutorial, we will show you how to install Telnet and how to access the remote system via Telnet.


Installation

Open the terminal and enter the following command to install Telnet:

Yum Install Telnet telnet-server-y

Telnet is now installed on your server. Next, edit the file/etc/xinetd.d/telnet:

Vi/etc/xinetd.d/telnet

Set disable = no:

# Default:on
# description:the Telnet Server serves Telnet sessions; It uses \
# unencrypted Username/password pairs for authentication.
Service Telnet
{
Flags = Reuse
Socket_type = Stream
wait = no
user = root
Server =/usr/sbin/in.telnetd
Log_on_failure + = USERID
Disable = no
}

Save and exit the file. Remember that we don't have to do this in CentOS 7.


Next, use the following command to restart the Telnet service:

In the CentOS 6.x system:

Service xinetd Start

Let the service start on every reboot:

On CentOS 6:

Chkconfig Telnet on
Chkconfig xinetd on

On CentOS 7:

Systemctl Start Telnet.socket
Systemctl Enable Telnet.socket

Allow Telnet to default port 23 through firewalls and routers. To make the Telnet port available through the firewall, edit the following file in the CentOS 6.x system:

Vi/etc/sysconfig/iptables

Add the following line "-A input-p tcp-m State--state NEW--dport 23-j ACCEPT":

# Firewall configuration written by System-config-firewall
# Manual Customization of this file are not recommended.
*filter
: INPUT ACCEPT [0:0]
: FORWARD ACCEPT [0:0]
: OUTPUT ACCEPT [0:0]
-A input-m state--state established,related-j ACCEPT
-A input-p icmp-j ACCEPT
-A input-i lo-j ACCEPT
-A input-p tcp-m state--state NEW--dport 23-j ACCEPT
-A input-m state--state new-m tcp-p TCP--dport 22-j ACCEPT
-A input-j REJECT--reject-with icmp-host-prohibited
-A forward-j REJECT--reject-with icmp-host-prohibited
COMMIT

Save and exit the file. Restart the Iptables service:

Service Iptables Restart

In CentOS 7, run the following command to allow the Telnet service to pass through the firewall.

Firewall-cmd--permanent--add-port=23/tcp
Firewall-cmd--reload

That's it. Now the Telnet service is ready to use.


Create user

Create a test user, for example, the username is "SK" and the password is "CentOS":

Useradd SK
passwd SK

Client Configuration

To install the Telnet package:

Yum Install Telnet

In a Deb-based system:

sudo apt-get install Telnet

Now, open the terminal and try to access your server (remote host).

If your client is a Linux system, open the terminal and enter the following command to connect to the Telnet server.

Telnet 192.168.1.150

Enter the user name and password that you have created on the server:

Example output:

Trying 192.168.1.150 ...
Connected to 192.168.1.150.
Escape character is ' ^] '.

Kernel 3.10.0-123.13.2.el7.x86_64 on an x86_64
Server1 Login:sk
Password:
[Email protected] ~]$

As you can see, the remote host has been successfully accessed locally.

If your system is windows, go to start-to-run command prompt.

At the command prompt, enter the command:

Telnet 192.168.1.150

192.168.1.150 is the remote host IP address.

Linux centos/rhel/scientific install Telnet on Linux 6 & 7

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.