If you have used the Internet today, you have used many machines running OpenSSH. Cisco, Juniper and other brands of routers are maintained using OpenSSH. Nearly all web servers, dns servers and most mail severs are accessed by system administrators using OpenSSH.
On October, 25th, 1999. the First release (http://www.openssh.com/openssh_pr.txt) of OpenSSH was made public. Since then, it has risen to take over 80% of the market (http://www.openssh.org/usage/ssh-stats.html), with virtually zero marketing.
Any day you use the net, you are using and relying on dozens if not hundreds or thousands (depending on your day) of machines operated and maintained via OpenSSH. The OpenSSH client is included by default most operating system distributions, including OS X, Linux, BSD and Solaris. During the first ten years of its existence, ssh has largely replaced older corresponding unencrypted tools and protocols. Nowadays, hosts are subject to hostile scans from the moment they are connected to the network. Any and all unencrypted traffic is scanned and parsed for user names, passwords and other sensitive information. OpenSSH users have that much less to worry about.
This Open Source Project has Free Licensing, weighted towards the developers' flexibility, and is famous for Strong Encryption (3DES, Blowfish, AES, Arcfour). However, this suite of tools offers a lot more. Here is a small sample:
- X11 Forwarding (encrypt X Window System traffic)
- Port Forwarding (encrypted channels for legacy protocols)
- Strong Authentication (Public Key, One-Time Password and Kerberos Authentication)
- Agent Forwarding (Single-Sign-On)
- Interoperability (Compliance with SSH 1.3, 1.5, and 2.0 protocol Standards)
- SFTP client and server support in both SSH1 and SSH2 protocols.
- Kerberos and AFS Ticket Passing
- Data Compression
OpenSSH (http://openssh.org/donations.html) is one of the three tools to master for any aspiring system administrators who wish to become competent or proficient at their trade.