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amazon-ec2linux-kerneltelnetputty

How to set up telnet in AWS instance?

I got SSH working fine. But I am facing an issue with connecting via telnet.

Outbound

Inbound

Putty

Solution

  • ssh is recommended over telnet, as telnet is not encrypted and is by default not installed in amazon instance.

    However if needed, steps involved for Linux : Amazon Instance or Centos

    1. Install telnet daemon in the instance: Install telnet-server using sudo yum install telnet-server . Package telnet is for the client program in case one want to connect using telnet client from the instance, not needed for the exercise.

    2. Enable the telnet daemon service: - By default the service is disabled in /etc/xinetd.d/telnet, The disable flag needs to be set to no.

      service telnet { flags = REUSE socket_type = stream wait = no user = root server = /usr/sbin/in.telnetd log_on_failure += USERID disable = yes }

      Post change it should look like below service telnet { flags = REUSE socket_type = stream wait = no user = root server = /usr/sbin/in.telnetd log_on_failure += USERID disable = no }

      Verify the configuration in case of any edit related errors. sudo chkconfig xinetd on

    3. Bring up the telnet service:

      Bring up the telnet daemon as root using sudo service xinetd restart command

    4. Enable inbound telnet default port (23) on AWS Console: In AWS Console EC2/Security Groups/<Your Security Group>/Inbound, set a rule

      Type:Custom-TCP Rule

      Protocol: TCP Range

      Port Range: 23

      Source: <As per your business requirement>

    5. Test the telnet connection: Test the telnet connection from any client enabled in the firewall.

      >telnet ec2-XX-XX-XXX-XXX.region.compute.amazonaws.com. Connected to ec2-XX-XX-XXX-XXX.region.compute.amazonaws.com. Escape character is '^]'. Password:

    The steps(tools) will vary slightly for other linux variants.

    PS: Referred http://aws-certification.blogspot.in/2016/01/install-and-setup-telnet-on-ec2-amazon.html, fixed few issues in the commands.