Make Tech Easier » ssh

How to Use ‘remote:/’ KIO and KNetAttach

Tavis J. Hampton — Mon, 31 Aug 2009 12:20:17 +0000

In my post two weeks ago, I introduced you to KDE’s KIO slaves and gave you a brief overview of the services they offer. One of the KIO protocols is remote:/, which relies on KNetAttach to create virtual network folders. With it, you can create folders for the following services:

1. WebFolder (webdav)
2. FTP
3. Microsoft Windows network drive (using Samba)
4. Secure shell (ssh)

Each one has its slightly unique features and requirements, and in this post, you will learn about each one.

There are two ways to start KNetAttach. One, which we already discussed, is to go to remote:/ in Dolphin or Konqueror. Then, simply click on Add Network Folder. The other method is to press Alt-F2, type “knetattach” and press Enter.

WebFolder

WebFolder relies on WebDAV, which allows you to create and use web-based folders. Many remote file storage services rely on this technology. To connect to a web folder:

1. Select WebFolder from the “Add Network Folder” list and click “Next“.
2. Give it a name; something you will only use for identification.
3. Enter your username.
4. For Server, it is usually a full web address like http://webdav.yourdomain.com
5. Enter a folder name only if required by your host.
6. Check “use encryption” if HTTPS is available.
7. Check “create an icon for this remote folder” to use the connection again in the future.
8. Click “Save and Connect“.

It will prompt you for your password. If you elect to save your password, it is a good idea to use Kwallet, which is enabled by default.

FTP and SSH

Connecting to FTP is nearly identical to other connection methods.

1. Give the connection a name.
2. Enter the username (Often, this is a full email address if you use shared hosting. Check with your host). If it is public FTP, usually the username is “anonymous”.
3. Enter the server (Usually just the domain name, like suchandsuch.com or ftp.suchandsuch.com).
4. Only change the port if specified by your host. 21 is the default.
5. Click “Save and Connect“.

The only difference with SSH is usually the port number. In addition to connecting to remote hosts for a website, this is a good method to use for connecting two Linux computers on a local network for file transfer. Just make sure that both hosts have openssh server installed.

Microsoft Windows network drive

For a connection to Windows, you will need Samba running and configured on your computer. If you are unsure what server information to use, navigate to remote:/ and then click on “Samba Shares“. It will show you the current windows shares on your network. When you click “Save and Connect“, it will prompt you for a username and password only if the samba share requires it.

Network Services

There is a button in the remote:/ section called “Network Services”, and it allows you to connect to zeroconf services. The idea behind zeroconf (zero configuration) is to connect to networked computers, printers, and various devices without any expert configuration. Linux uses a free implementation called Avahi. Many distributions enable the avahi daemon by default. It allows you to quickly discover and connect to FTP, Samba, HTTP, CUPS, and other protocols.

The remote:/ KIO combined with KNetAttach provides users with a full networking experience. Once you are connected to one of the above-mentioned services, you can navigate through them just as you would through folders and files on your own computer. You can drag and drop, copy and paste, and even delete all in real time. When you are finished, just close the tab or window.

How to Use ‘remote:/’ KIO and KNetAttach originally published on Make Tech Easier (RSS)

2 Useful SSH Tricks to Improve Your System Security

Joshua Price — Thu, 02 Jul 2009 12:33:53 +0000

A few days ago, Tavis wrote a great article on How to use SSH X-forwarding to Run Remote Apps. X forwarding is indeed a very handy feature of SSH, so I thought it would be a good time to expand on some of the other great uses for this excellent piece of software (and some related tools). Today, we’ll cover SCP and SSHFS.

To follow this guide, you’ll need the following:

- Client computer with openssh-client installed (for Windows, use Putty)
- Server computer with openssh-server installed (Available on any UNIX-style system)
- A working set of login credentials on the server

If you don’t have a computer with an SSH server, you can use the same PC as both client and server for the sake of trying all this out. If you do have a (Linux, Unix, BSD) computer available to act as server, make sure to install the OpenSSH server software. Debian and Ubuntu users can get this easily with

sudo apt-get install openssh-server

1. Using SSH to securely copy files

This is my second favorite use for SSH. When you install the OpenSSH client on your machine, it typically comes with a file copy tool called SCP (Secure Copy). This can be VERY useful as a way to not only send files to your friends (who have openssh-server running) but to do it in a completely encrypted way.

For example, a friend of mine in Michigan is a studio engineer. He mixes audio tracks for a recording studio. Sometimes, when he wants a second opinion, he’ll send me what he’s working on so I can give him my opinion. Now, since this is all copyrighted music which has not even been released to the public, he’s naturally reluctant to post it on a filesharing service or web site, and the files are often too large for email. Instead, we transfer using SCP.

The format for an scp command is:

scp filename user@remote-host:/where/to/save/it

So my friend, on the other side of the country, would enter something like

scp MyNewMix.wav nick@joshs-computer.com:/home/nick/mixes

This example is assuming my computer is accessible from joshs-computer.com and that he has a user account on it named nick. His file will be copied to my computer over a fully encrypted connection without having to be stored at some third-party website or email server.

2. Mount a network drive securely

Now here is my #1 favorite use of SSH. If you’re a Linux user, you’re probably familiar with mounting drives. You have a device like a cdrom drive (say, /dev/hdc for example), and to access it, you mount it to a directory such as /media/cdrom. Well you can use that same principle with a program called SSHFS to mount a filesystem over a network/internet and attach it to a directory on your computer.

SSHFS is not part of the standard openssh package. It’s a separately developed program that you’ll install independently using your normal package manager.

Let’s go back to the example with my friend at the studio. Perhaps he’s got several new mixes for me instead of just one, or perhaps we do this so often that using SCP to transfer back and forth starts to become a hassle. Well, if he’s got openssh-server installed and I have an account on his computer, I can mount his hard drive to any directory I wish. The command follows the structure:

sshfs user@remote-host:/what/I/want /where/to/put/it

So to connect to Nick’s computer I’d use something like:

sshfs josh@nicks-computer.com:/home/nick/mixes /home/josh/nicks-computer

That would make it so that any time I access the folder /home/josh/nicks-computer from my machine, it would actually connect to Nick’s computer over SSH and give me access to all those files just as if they were sitting in a normal directory on my computer. Any changes I make are made to the files on his computer, it’s completely transparent. I can use whatever audio software I like to work with the files, they are completely oblivious to the fact that they’re really reading the file from 2500 miles away.

A word of warning about SSHFS: since it’s reading the files over the internet instead of locally, combined with the encryption overhead, SSHFS can be SLOW. You probably wouldn’t want to use it to access files that need lots of speed or are constantly being read or written.

There are many great uses for SSH and related tools. I’d love to hear what other tricks you may have. SSH tunneling, for example, can be hugely beneficial for some people, but doing it justice would require an article of its own. Do you have any other tips to get the most out of SSH?

2 Useful SSH Tricks to Improve Your System Security originally published on Make Tech Easier (RSS)

How to use SSH X-forwarding to Run Remote Apps

Tavis J. Hampton — Mon, 22 Jun 2009 12:12:06 +0000

There are times when it is just quicker, easier or even necessary to use a graphical application, and there are also times when you might be away from the computer that has your crucial applications installed. Whatever the scenario, Linux and other operating systems running an X server have the ability to forward a graphical application through SSH. Following a few simple steps, you can run a remote application in all of its full graphical glory.

Installation and setup

Before you begin you need to make sure that SSH client and server are installed on the correct computers. The host computer that will have the actual running applications needs to have SSH server running. On Ubuntu, it is not installed by default. Look for the packaged called “openssh-server” and install it. On the client computer, you will need “openssh-client“.

The other important preliminary step is to make sure both computers are connected to a network and that you can reach them via SSH. If the computers are in the same building, it will be easy. If not, you might have to configure the host computer to receive SSH connections through the firewall. See your router’s documentation for the correct method of port forwarding.

Connecting

1. Open a terminal emulator: Gnome terminal, Konsole or something similar.

2. Now connect to the host computer. As an example, if the host IP address is 192.168.254.76 and the host username is “bobolina”, you would type the following:

ssh -X -lbobolina 192.168.254.76

This tells SSH to forward the X server calls to the client computer.

3. At the password prompt, enter the password.

4. Run the application. For example, if you want to run Kwrite, just type the command:

dbus-launch kwrite &

(Note: you will need to have “dbus-launch” before KDE 4 applications. Other applications that do not require D-Bus should work without it).

Other Considerations

That is all it takes. You should now be able to run remote X applications at will. This can be very helpful if, for example, you are running a computer with a very small hard drive, no hard drive at all or even one without a CD-ROM drive, all of which are common with many netbooks and low-cost mini desktops.

To automate this process, you could setup SSH public keys to connect without passwords and write an executable script. Also, if you need a full X session forwarded, you can use NX technology, available with the commercial NoMachine NX or with FreeNX (a free and open source alternative).

As with any network solution, security is always a concern. Using SSH provides a secure connection, but it does little good if your password is easy to guess and your firewall allows anyone to gain access to it. Once you have a secure plan in place, remote X forwarding is an excellent way load remote applications on demand and manage remote machines. The possibilities are only as limited to your imagination and the speed of your network connection. Experiment with different techniques, and let us know what you discover.

How to use SSH X-forwarding to Run Remote Apps originally published on Make Tech Easier (RSS)