tailieunhanh - 7 Things Every System Administrator Should Know About OpenSSH

OpenSSH is an open-source implementation of the SSH (Secure SHell) protocols, originally developed in 1995 by Tatu Ylönen. SSH-based tools provide secure client/server connections and are usually designed to replace older remote-access tools like rsh and telnet. Unlike their predecessors, SSH-based tools encrypt their transmissions, making it difficult or impossible for intruders to “sniff” important information, such as passwords, from the data stream. SSH implementations exist for every major platform including Microsoft Windows. This paper will focus on the OpenSSH implementation | Global Knowledge Expert Reference Series ofWhite Papers 7 Things Every System Administrator Should Know About OpenSSH 1-800-COURSES 7 Things Every System Administrator Should Know About OpenSSH Brad Smith Red Hat Instructor RHCE Introduction OpenSSH is an open-source implementation of the SSH Secure SHell protocols originally developed in 1995 by Tatu Ylonen. SSH-based tools provide secure client server connections and are usually designed to replace older remote-access tools like rsh and telnet. Unlike their predecessors SSH-based tools encrypt their transmissions making it difficult or impossible for intruders to sniff important information such as passwords from the data stream. SSH implementations exist for every major platform including Microsoft Windows. This paper will focus on the OpenSSH implementation which was initially developed as part of the OpenBSD project and is installed by default on most modern BSD and Linux-based operating systems including Red Hat Enterprise Linux and Fedora. The goal of this paper is to provide a brief introduction to several techniques for getting the most out of this powerful tool. More information on most of these topics can be had from the ssh and related man pages as well as the openssh website http . The Basics The most essential thing to know about OpenSSH is how to use the OpenSSH client simply called ssh to connect to an SSH server. Note that the server does not have to be the one provided by OpenSSH. Any server that supports the SSH protocols may be used. Below is an example of a simple ssh connection from a system called satsuki to a system called mei brad@satsuki ssh mei The authenticity of host mei can t be established. RSA key fingerprint is b2 8d aa 5a 32 f8 21 79 25 c1 cd 3b a9 4c d4 7d. Are you sure you want to continue connecting yes no yes Warning Permanently added mei RSA to the list of known hosts. brad@mei s password Last login Sat Jul 28 11 29 40 2007 .