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Re: [LUG] Using SSH

 

On Friday, 28 February 2020 13:47:05 GMT Neil wrote:
> 
> I wanted to look at an image on another computer, as a test. So I used
> ssh -Y to link to it, opened the relevant folder and used feh to view
> the image. All seemed to work.
> 
> Is this a good way to go, or should I be using something else?

My understanding is that "ssh -Y" enables X11 forwarding.

X11 is an old and complex protocol; age and complexity tends to be bad for 
protocols, because network folk were less paranoid in the past, and complexity 
means it is hard to understand the full implications of enabling it. 

There has been work to add a security layer to X11, it probably won't protect 
you from the NSA or similar because of the complexity and extensions.

On the other hand if the remote system is trusted, or you have no reason to 
believe it has been compromised by advanced hostile hacking teams intent on 
accessing your computer, life with X11 Forwarding is good, and we use to have 
fun back in the 1990s sending silly things around the network (things were 
rather less secure still back then).

Last time I used it in anger was the launch of Oracle 8, when you needed an 
X11 server in order to run the Java installer for HP-UX, to be able to do a 
command line installs of their RDBMS (I have no idea how they released such 
broken tools after Oracle 7.3.4, it tooks ages for them to sort it out). I 
think I did some messing around 17 years ago trying to make something else 
work with Hummingbird X11 for Windows or some such but it was horrid, and I 
ran away screaming (mostly the Windows X11 implementation to be fair).

From a "I want to see lots of files on a computer I have SSH access to", the 
obvious alternative choice is SSHFS, which makes an ssh connection work like a 
file system using "sftp". See "man sshfs". This should be reasonably robust 
security-wise too.

There are some set-up Wizards in the various graphical user desktops for this 
type of access. e.g. In KDE Dolphin just click "Add Network Folder" and fill in 
the details as you would for the SSH command line, pick "SFTP"*, the remote 
folder you want to see "/home/simon" say and it is doing the same thing but 
with a shiny GUI, and will bookmark it for later. And you can access the 
folder with all your familiar tools etc.

KDE also offers FISH rather than SFTP, which is a file transfer over shell 
protocol. They were horrid enough back in the days of serial comms (Kermit and 
YModem, Zmodem etc), I have no idea why people reinvented it, or why KDE is 
still offering it. Possibly they had really complex multi-hop file transfers or 
long dead operating systems or both. If anyone knows the history of this 
please share.



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