Installing ssh on S.u.S.E. Linux

http://www-hera-b.desy.de/subgroup/computing/sshinst.html

Why?

Because every password you type after using rsh, rlogin, xrsh, xrlogin, telnet, or ftp is transmitted as clear ASCII text over the network. This way, any root user running a simple tool to dump the TCP/IP traffic can collect passwords. These tools come with a number of operating systems. Different from the above, sshoffers you encryption of all information transmitted in your session.

Although ssh comes with the SUSE Linux distribution, it is always a good idea to get the latest release from http://www.cs.hut.fi/ssh/ or the German mirror ftp://ftp.cert.dfn.de/pub/tools/net/ssh. As of this writing, this is ssh-1.2.26.tar.gz of 10-July-1998. The archive comes with a PGP signature.

 

How?

Your SUSE Linux may have ssh already installed. If so, the binaries will live in /usr/bin and /usr/sbin, documentation in /usr/manand so on. The description below will result in overwriting this installation. An alternative is outlined at the end.

 

  1. Unpack the archive using tar xzf ssh-1.2.25.tar.gz
  2. Change into the newly created ssh-1.2.25 directory
  3. Change the installation prefix in the configurescript by editing the line
    ac_default_prefix=/usr/local

    to

    ac_default_prefix=/usr
  4. Type ./configure
  5. Type make
  6. If there were no errors, become root (you haven’t done the above as root, have you? 😉 and type make install
  7. To automatically start the sshd deamon at boot time for handling incoming connections, place the following script in /sbin/inet.d, name it sshd, and set symbolic links K20sshd and S20sshd in /sbin/init.d/rc3.d to this script. (Note: If you had ssh already installed, just replacing the script will do the job; the symlinks are already there.)

    #! /bin/sh
    #
    # start or stop the secure shell daemon - kwo 971125
    #
    #/sbin/init.d/sshd
    
    case "$1" in
        start)
            if [ -x /usr/sbin/sshd ]; then
                echo "starting ssh daemon."
                /usr/sbin/sshd
            fi
            ;;
        stop)
            echo -n "stopping ssh daemon:"
            killproc -TERM /usr/sbin/sshd
            echo
            ;;
        *)
            echo "Usage: $0 {start|stop}"
            exit 1
    esac
    
    exit 0

  8. Type /sbin/init.d/sshd start to start the daemon. (Note: If you already have a daemon running, stop that first.)

It is not an installation alternative to change the path in step 3). This will prevent the next Linux update from overwriting the installation, but may cause conflicts if you ever install ssh from a distribution CD. You will have to modify the path in the above script if you chose this solution.

If you have ssh installed with your Linux distribution, but the daemon is not running, you may have to enable START_SSHD in your system configuration file. You can use YAST to do this. Replacing /sbin/init.d/sshd with the above script will also do the job.

Main parts of this description were adopted from Knut Woller’s web page “Installing ssh on S.U.S.E. Linux”.