Posted by: isaraffee | August 29, 2009

Configuring telnet in Dreamlinux 2.2

Configuring telnet in Dreamlinux 2.2

In this exercise, the telnet server is the Ubuntu server and the Dreamlinux server will be the telnet client. So the title for this section should read “Configuring telnet server in Ubuntu”. There is nothing to be configured on the telnet client, other than having the telnet client script called telnet Anyway this is how we configure telnet server in Ubuntu.

Configuring telnet server in Ubuntu

You need to install inet

But before that check that inet or xinetd is not install

root@ismailrocks:/etc/init.d# ls x*

x11-common xserver-xorg-input-wacom

root@ismailrocks:/etc/init.d# ls i*

ls: i*: No such file or directory

root@ismailrocks:/etc/init.d#

Install telnetd

root@ismailrocks:/etc/init.d# apt-get install telnetd

Selecting previously deselected package openbsd-inetd.

(Reading database …

144599 files and directories currently installed.)

Unpacking openbsd-inetd (from …/openbsd-inetd_0.20050402-6_i386.deb) …

Selecting previously deselected package telnetd.

Unpacking telnetd (from …/telnetd_0.17-35ubuntu1_i386.deb) …

Setting up openbsd-inetd (0.20050402-6) …

* Stopping internet superserver inetd [ OK ]

* Not starting internet superserver: no services enabled.

Setting up telnetd (0.17-35ubuntu1) …

Check if telnetd is installed

root@ismailrocks:/etc# dpkg -l | grep telnet

ii telnet 0.17-35ubuntu1 The telnet client

ii telnetd 0.17-35ubuntu1 The telnet server

I tried to search for telnetd via find command but failed to locate any telnetd scripts.

Paradoxically we are searching for a package openbsd-inet which will run the telnetd service. In Linux the inetd script is also know as the internet superserver script

root@ismailrocks:/etc/init.d# dpkg -l | grep openbsd-inetd

ii openbsd-inetd 0.20050402-6 The OpenBSD Internet Superserver

root@ismailrocks:/etc/init.d# ll openbsd-inetd

-rwxr-xr-x 1 root root 2324 2007-04-27 21:06 openbsd-inet

openbsd-inetd is a script to start telnetd

root@ismailrocks:/etc/init.d# ./openbsd-inetd

Usage: /etc/init.d/inetd {start|stop|reload|force-reload|restart}

Before you start inetd, type:

root@ismailrocks:/etc/init.d# ps -ef|grep inetd

root 6753 6382 0 15:19 pts/1 00:00:00 grep inetd

This shows that inetd is not running

Start inetd, by typing:

root@ismailrocks:/etc/init.d# ./openbsd-inetd start

  1. Starting internet superserver inetd [ OK ]

Check that inetd is running

root@ismailrocks:/etc/init.d# ps -ef|grep inetd

root 6774 1 0 15:19 ? 00:00:00 /usr/sbin/inetd

Now let’s telnet into this Ubuntu telnet server from another server, in my case, the Dreamlinux server. But before that it’s interesting to check that tenetd is not running on the telnet server. To see this, type:

root@ismailrocks:/etc/init.d# ps -ef|grep telnetd

root 6938 5571 0 15:22 pts/0 00:00:00 grep telnetd

You will see that telnetd is not running, and you don’t have to start it. This is because the inetd service will start once it receives a telnet connection from other terminals.

Now telnet to the telnet server.

root@ismailrocks:/etc/init.d# telnet 192.168.1.100

Trying 192.168.1.100…

Connected to 192.168.1.100.

Escape character is ‘^]’.

Ubuntu 7.10

ismailrocks login: ismail

Password:

Last login: Tue Aug 11 15:21:56 SGT 2009 from ismailrocks.local on pts/2

Linux ismailrocks 2.6.22-16-generic #1 SMP Mon Jan 26 00:07:52 GMT 2009 i686

ismail@ismailrocks:~

On the telnet server you can check that the telnet server service, telnetd is started automaticaly by inetd. To see this type:

ismail@ismailrocks:~$ ps -ef|grep telnetd

telnetd 7086 6774 0 15:26 ? 00:00:00 in.telnetd: ismailrocks.local

Ok let’s now reverse role, Ubuntu becomes the telnet client and Dreamlinux becomes the telnet server.

On the Dreamlinux, check that openbsd-inetd (also known as the internet superserver), which handles the telnet requests.

root@mars:/etc/init.d# ls -l openbsd-inetd

-rwxr-xr-x 1 root root 2354 Sep 11 2006 openbsd-inetd

Yes, it is installed. If it is not installed, type:

root@mars:/etc/init.d# apt-get install telnetd

Now start the inetd service.

root@mars:/etc/init.d# ./openbsd-inetd start

  • Not starting internet superserver: no services enabled.

I received the above error because telnetd is not enable in the /etc/inetd.conf file. So add in the telnetd service in the /etc/inetd.conf file by typing the following line.

root@mars:/etc# nano inetd.conf

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

After you have edited the /etc/inetd.conf file (I use nano for editing), start the inetd service on the telnet server i.e. the Dreamlinux server.

root@mars:/etc/init.d# ./openbsd-inetd start

Starting internet superserver: inetd.

Now from a telnet client, in my case the Ubuntu server, type;

root@mars:/etc/init.d# telnet 172.16.0.2

Trying 172.16.0.2…

Connected to 172.16.0.2

Escape character is ‘^]’.

Debian GNU/Linux 4.0

mars login: ismail

Password:

Last login: Wed Dec 1 09:06:10 1999 on :0

Linux mars 2.6.18.1-kanotix-1 #1 SMP PREEMPT Wed Nov 29 15:15:15 EST 2006 i686

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