I know that tools like xdotool can do the job, but it's not pre-installed.
I want to use the low-level API (i.e. the X Window client and server protocol directly).
I connect the server using nc -U /tmp/.X11-unix/X0 successfully in Ubuntu 20.04, but I don't know which command to send.
Related
I am looking to use asyncssh with python3.7 (asyncio)
Here is what I want to build:
A remote device would be running a client that does a call-home to a centralized server. I want the server to be able to execute commands on client using reverse ssh tunnels on the incoming connection. I cannot use forward ssh (regular ssh) because the client could be behind NAT and server might not know the address of the client. I prefer client doing a call-home and then server managing the client.
The program for a POC should use python3 + an async implementation of ssh. I see asyncssh as the only viable choice (please suggest if you have an alternate):
Client: Connect to server and accepts reverse ssh tunnels to be opened on same outbound connection
Server: Accepts connection from client and keeps the session open. The server then opens reverse ssh tunnel to the client. For e.g. the server program should open 3 reverse ssh tunnnels on the incoming connection. Each of these tunnels would run one command ['ls', 'sleep 30 && date', 'sleep 5 && cat /proc/cpuinfo']
Server program should print the received response for each of these commands (one should come back amost immediately, other after 5 and other after 30).
I looked at the documentation, and I could not see examples of using multiple reverse ssh tunnels.
Anyone has experience using this? Can you point me to examples?
Developer of asyncssh has provided an example:
As of now, this is in develop branch. I have tested it and it does the job perfectly!
https://asyncssh.readthedocs.io/en/develop/#reverse-direction-example
[If you are checking this after a while, you might find it in master documentation.]
I would like to use RStudio for analysis of data on a MySQL instance. This is a AWS RDS MySql instance that is only accessible via a jump box / bastion host. I have the credentials necessary to connect to the jump box, and from the jump box to the RDS instance. What do I need to do be able to query this DB directly from within the RStudio console?
I can connect (using the Terminal tab in RStudio)to the jump box using:
ssh -p 22xx user#ip.add.re.ss
Then I can connect to RDS mysql using:
mysql -u username -p database -h hostname.us-east-1.rds.amazonaws.com
I can connect and do manual mysql commands from within RStudio terminal, but I don't seem to be able to do anything with the DB from the RStudio console.
Sorry for opening a 2yo thread, but for everyone dealing with this issue as I am - I found this thread and it looks like it works (connecting with MySQL via ssh from R Studio).
You should use something which is called port forwarding. Some details
are here
(https://help.ubuntu.com/community/SSH/OpenSSH/PortForwarding) For
example, say you wanted to connect from your laptop to
http://www.ubuntuforums.org using an SSH tunnel. You would use source
port number 8080 (the alternate http port), destination port 80 (the
http port), and destination server www.ubuntuforums.org. :
ssh -L 8080:www.ubuntuforums.org:80 Where should be
replaced by the name of your laptop.
This is done for whole computer so you dont need to do this from r
studio.
Offcourse you need to forward your port to 3036. But you need special
privilige on the server. Because on most hosting you can only connect
from localhost (for example from PHP)
Source: https://www.py4u.net/discuss/881859
I'm trying to use Google's Colab feature to connect to a remote run-time that is configured with HTTPS. However, I only see an option to inform the port on the UI, not the protocol.
I've checked the Network panel and the website starts a WebSocket connection with http://localhost:8888/http_over_websocket?min_version=0.0.1a3, HTTP-style.
Full details of my setup:
I have a public Jupyter server at https://123.123.123.123:8888 with self-signed certificate and password authentication
I've followed jupyter_http_over_ws' setup on the remote
I started the remote process with jupyter notebook --no-browser --keyfile key.pem --certfile crt.pem --ip 0.0.0.0 --notebook-dir notebook --NotebookApp.allow_origin='https://colab.research.google.com'
I've created a local port forwarding with ssh -L 8888:localhost:8888 dev#123.123.123.123
I've turned on network.websocket.allowInsecureFromHTTPS on Firefox
I've went to https://localhost:8888 and logged in
Naturally, when the UI calls http://localhost:8888/http_over_websocket?min_version=0.0.1a3 it fails. If I manually access https://localhost:8888/http_over_websocket?min_version=0.0.1a3 (note the extra s) it gets through.
I see three options to solve it:
Tell the UI to use secure WS connection
Run a proxy on my local machine to transform the HTTPS into plain HTTP
Turn off HTTPS on my remote
The last two I think will work, but I wouldn't like that way.
How to do #1?
Thanks a lot!
Your option 1 isn't possible in colab today.
Why do you want to use HTTPS over an SSH tunnel that already encrypts forwarded traffic?
When I use WinSCP in Windows to connect to VMware with Ubuntu, it prompted this:
The server rejected SFTP connection, but it listens for FTP connections.
Did you want to use FTP protocol instead of SFTP? Prefer using encryption.
What's the matter?
I can succeed to ping Ubuntu in Windows.
The fact that you can ping the server has nothing to do with what protocols it supports.
The message says that the server does not listen on port 22 (SSH, SFTP), but listens on port 21 (FTP). The point of the message is that WinSCP defaults to SFTP protocol, what is not common. So it tries to help users who expect FTP to be a default. But that's not relevant to you apparently.
As #ps2goat suggested, make sure you setup SSH/SFTP server.
For more details, see the documentation for the error message The server rejected SFTP connection, but it listens for FTP connections.
If you see this error all of a sudden (when SFTP has always worked for you for this particular server), and if you are using CSF (ConfigServer Security & Firewall), then it might be that your IP was blocked for SSH access. Try flushing all blocks. Also, try restarting the SSH server.
Old question but still responding so others might get benefited.
I stumbled upon this error and the first thing I checked was if my ubuntu machine had ssh installed. It was there and the latest version and I still would get this error.
As long as you have ssh access to the target, check the ssh service status and most certainly it'd be found inactive. Turn it on using
sudo service ssh restart
and you should be back in the game.
Do check the status of the SFTP by using
sudo service ssh status
and take any corrective action.
I would like to send an email through a remote SMTP server. How can this be done? I will be sending the email from a bash shell script.
I'm using a unix machine. uname -a returns:
Linux linux 2.4.21 BrandZ fake linux i686 athlon i386 GNU/Linux
Contacting a remote SMTP server directly is not generally the way this is done. What, for example, if the server is temporarily unavailable?
The easier route is to run a local mailserver such as postfix, exim or qmail, and set it up to send mail through a remote server. Then you can just use command-line sendmail to send your e-mail.
In postfix on Ubuntu, I put the following in master.cf:
relayhost = [smtp.my-isp.com]
smtp_generic_maps = hash:/etc/postfix/generic
You need the last line in case your ISP's mail server requires that all outgoing mail originates from you#your-isp.com. Then you'll also need /etc/postfix/generic like this:
youruser#localhost you#your-isp.com
Add other variants (e.g. youruser#yourbox.yourdomain) as necessary.
The mailx command can be used to send email non-interactively,
but the classical implementation talks to a local mail transport agent.
There are simple MTAs which will just send email through a remote SMTP server,
and won't accept any local email.
Another solution is to use heirloom-mailx,
(formerly known as nail I think)
which supports talking to an SMTP server directly instead of using a local MTA.
For instance, you may invoke it as follows:
heirloom-mailx -S smtp=smtp.your-isp.com \
-S from=you#your-isp.com \
-s "subject" <<EOM
Hello, $name,
This is an automatic reminder, sent out once a month, ...
[the rest of your message]
EOM
i'm not sure if it still works.. but you might wanne use telnet. at least you should be able to write a bashscript using it