[pbeveridge]

Hi there,

wondering if anyone can help a noviciate solve this one...

I would like to work on the terminals in my SGI 2 through an ssh tunnel on my linux pc. 

Is the command  on the linux 

ssh -L  port number:localhost:portnumber user@SGI 2 or IP

and then with IRIX installed on the  SGI 2, is it

SSH -R port number:localhost:portnumber user@linuxpc or IP

If anyone knows how to set this up, and can offer some advice I would much appreciate it. 

p.s. How I find the port numbers, or assign ports I do not know...

[vishnu]

Inside my LAN (which is protected by a very secure firewall, the configuration script for which I wrote myself) I just use telnet, which obviates all the overhead of encrytion/decryption in ssh.

[pbeveridge]

Okay, I'll check out telnet.. Thanks for the tip

[pbeveridge]

telnet worked fine, thanks for suggesting it

apparently I should have the same response typing

ssh SGI 2

but instead received

connection refused: port 22

Not sure why.. ?

[vishnu]

You've got to turn port 22 on in your /etc/services file.

[robespierre]

/etc/services doesn't "turn on" anything, it is simply a list. You have it confused with inetd.conf.

ssh has X11 forwarding, which may be what was called "tunneling". This sets the DISPLAY environment variable to point to the ssh connection, so that typing "xterm" in a ssh session will open a window on your screen instead of on the remote computer. It is set up with a config file, see "man ssh_config".

There are a lot of limitations of X11 forwarding because of its security concerns, and because the SGI uses GL or OpenGL for its interface instead of vanilla X11.

There is a more basic ssh feature called the control port, which lets you share multiple activities (such as file copies and shells) over a single ssh connection. See "ControlPath" in "man ssh_config".

The port forwarding commands like -L, -R, or -D are for passing Internet sockets over the ssh connection. This is only useful when you want to make it look like your Internet traffic is originating from the ssh server (in other words, there is no point using them on a local network).

Telnet doesn't do any of this stuff (but ironically, Kerberized Telnet does do encryption, so there is nothing that restricts it to local networks).

For more convenient text-mode work on a remote computer, you could also use screen or tmux.

[foetz]

ssh SGI 2

but instead received

connection refused: port 22

Not sure why.. ?

because hostnames can't have spaces. use the ip instead and/or assign a proper hostname.
https://www.rfc-editor.org/rfc/rfc1123#page-13

[pbeveridge]

Thank you for these very helpful replies.

The discovery of telnet was a revelation. I could type commands on my linux PC for the SGI 2 and the SGI 2 would then carry the commands out.

Did telnet happen through just an ethernet connection between the linux PC and SGI 2? Both have ethernet going into a port switch, which also has a connection to the internet.

I've been wondering if I could create a connection from my home to the building a few miles where the SGI 2 is via the internet. I assumed that I'd have to use ssh to work on the SGI 2 from my other linux PC at home ?

[vishnu]

You can use telnet to connect to any computer on the network that has a telnet server that is listening for connections. The difference between telnet and ssh is that the telnet communication is not encrypted. That's why you should only use telnet on trusted networks. ssh packets are encrypted, probably (depending on your version) at 256 bit, which, while not uncrackable, is close enough to deter all but the most determined crackers.

[Shiunbird]

ssh has X11 forwarding, which may be what was called "tunneling". This sets the DISPLAY environment variable to point to the ssh connection, so that typing "xterm" in a ssh session will open a window on your screen instead of on the remote computer. It is set up with a config file, see "man ssh_config".

I recall doing X over telnet for HP-UX. Is there anything I am missing?
On the local machine, add remote machine to xhosts.
On the remote machine, set DISPLAY to the local machine, then start an application.