Individual Entry

ssh-ecurity — Part 1: What is ssh?

The internet is, in my opinion, one of the greatest advancements to mankind since the transistor. The transistor revolutionized our world making communications and information more accessible. The internet is now augmenting that revolutionary access to communications and information. Today, I can travel almost anywhere in the world and there it is — the internet. It's as ubiquitous as Starbucks but a much better product. I am virtually always in touch, thanks to the internet.

People can now accomplish things they used to have to do by physically traveling to a location. Shopping and banking, for example, have evolved with the internet by moving out of the physical realm of bricks and mortar buildings and into the virtual realm of bytes and silicon in the computer. People communicate more! The easy of sending an email is transforming the postal service from a letter carrying organization into a package delivery service competing with the likes of FedEx and US. People are more open and outspoken; sharing their thoughts with others via email and blogs. The internet has become a virtual "Speaker's Corner" in Hyde Park.

There are, however, some things I do on the internet that I would much prefer to keep private; especially, if I am using a public wireless! But how?

The answer:

There's a simple technology that I believe anyone and everyone using the internet should know and know how to use — ssh. From the command line, ssh is very powerful and simple to use. Some people prefer to use graphical front-ends to ssh such as PuTTY. I don't use PuTTY; however, the discussion here should enlighten you to ssh features which, with a bit of study, trial and error, can be exploited even when using one of the graphical utilities.

I decided to write a series of blogs on ssh, a most powerful tool, because I am amazed at how many people I encounter that simply don't know what ssh is.

So, what is ssh?

In simplest terms, it's secure shell. The term shell, as is used here, is the unix terminology for a command line interpreter or processor. However, I prefer to think of shell as a secure enclosure around communications. The shell that provides this security is encryption.

From the command line, ssh is as simple to use as telnet or its OpenVMS DECnet analog $ SET HOST. However, unlike its analogs, the communication between the client and server over the network is encrypted. Nothing is passed over the wire or airwaves, in the case of wireless networking, that can be readily captured and used by some nefarious type eaves-dropping on your session.

From the command line, using ssh is simple:

$ ssh

If you have the same username on the host you wish to connect to as on the host you wish to connect from, you can specify the destination without the username; it will default to being your current username.

$ ssh

In subsequent blogs, I will discuss some of the great features and benefits of using ssh. Even if you never use the command line, ssh is something everyone should know and appreciate.


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