Getting In

Apparently, the latest trend is to disable all of the remote login services, as well as file transfer, and just let the user connect to the system via remote desktop. That's because we, once again, can't be trusted to use the evil telnet responsibly but we're all fine when we let Microsoft tell us how to connect to our servers.

To get telnet working, you need to install two packages: xinetd; and telnet-server. While we're at it, we install the telnet package so that we can use the telnet client from the local machine, if need be. You can either install these packages when you build the system or you can install them via the package manager or command line. For example, on CentOS, you could try:

     su
     yum install xinetd telnet-server telnet

Or, on Ubuntu, you could try:

     apt-get install xinetd telnet-server telnet

Once the system is up and running, you need to enable xinetd because, even when it is installed by the package manager, the install does not turn it on or start it. You can do so like this:

     su
     /sbin/chkconfig on xinetd
     /etc/init.d/xinetd start

Or, you can pick the Services item from the System/Administration menu. From there, you can Enable the xinetd service and then start it.

Once xinetd is running, you need to edit the telnet configuration in the xinetd configuration directory. Change the line that reads "disable = yes" to "disable = no". The configuration file should look like this:

/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
     }

You should now be able to telnet to the system from a local command window by typing:

     telnet localhost

If this doesn't work, you may need to restart the xinetd server to get it to reread the telnet config file:

     su
     /etc/init.d/xinetd restart

Once you get a local telnet connection working, you need to make sure that the firewall will let outside telnet connections through. If you won't be using the firewall, now is the time to disable using the Firewall item on the System/Adminstration menu. Otherwise, you need to punch through port 23 on the firewall to let telnet in.

If you prefer to use ssh, instead of telnet, you simply need to install the rsh-server package. We also install the rsh package to give us the clients, which can be used on the local system to access other systems. For example, on CentOS, you could try:

     su
     yum install rsh rsh-server

Or, on Ubuntu, you could try:

     apt-get install rsh rsh-server

The sshd server should be enabled and started after the packages are installed. If not, you can start the server like this:

     su
     /etc/init.d/sshd start

Once again, you can test that you can log in via the local ssh client, before you go any further. Then, you need to make sure that the firewall will let outside ssh connections through. If you won't be using the firewall, now is the time to disable using the Firewall item on the System/Adminstration menu. Otherwise, you need to punch through port 22 on the firewall to let ssh in.