I just recently got into whatever you might call this stuff. I was just trying to send a java file over to the computer I ssh to. But when I went to do it, I just get told
sh: connect to host port 22: Connection timed out
lost connection
If possible I would like it explained very simply because of how new I am to this kind of stuff.
SSH to remote host(VM Ubuntu) from VS code terminal
Install VS Code with Remote Development extension pack.
Install Virtual machine (Virtual box) and Ubuntu running on it.
Check Ubuntu-Network-Settings-IPv4 address (10.0.2.15-default for VM).
Go to your virtual box Settings-Network-NAT Adapter (double-check).
Go to your virtual box Settings-Network-In Advanced-Port Forwarding.
Add this as given below and click ok and hereafter consider 127.0.1.1 for ssh.
portforwardinginVM
View the status and disable firewall settings in Ubuntu VM (ufw command).
In VS Code, View-Command Palette- Add new SSH host .
Add ssh username#127.0.1.1 and enter.
Or go to the terminal window (eg. Powershell) and type ssh username#127.0.1.1, it will ask if you want to update to host lists permanently, asking like yes/no and also your Ubuntu password to confirm.
Now try to connect to the host using username#127.0.1.1 and selecting OS like Ubuntu, then type the Ubuntu password.
That's it you are logged in to your virtual machine and can access files now from your local machine.
stuck from a couple of days. In ubuntu i'm creating vncserver with command line [tigervnc]
vncserver -localhost yes
to secure connection from only localhost.
vnc is successfully created with port - 5901.
Im using putty to establish SSH tunnelling,
SSH tunnel
in realVNC viewer in using
localhost:9091
But it gives error saying connection refused.
I want to establish a SSH tunnel with only localhost in order to avoid the brute force attack, getting too many authentication failure errors.
What am i doing wrong. Please guide me.
Note : connection works fine if i use vncserver -localhost no. But for security reasons i dont want this
to allow connection from localhost only and to avoid brute-force attack in these any settings need to change in vnc-config or something.
Did a hell of research, couldn't resolve. StackOverflow is the last hope.
Localhost is 127.0.0.1
You have to create SSH TCP FORWARD to localhost (or 127.0.0.1), not 103.16.26.144
There is how I use this on my linux desktop, from a shell terminal.
ssh -fL 9091:localhost:5900 user#103.16.26.144 sleep 2 &&
xvncviewer localhost:9091
Background
I have a machine in production running an elixir application (no access to iex, only to erl) and I am tasked with running an analysis on why we are consuming so much CPU. The idea here would be to launch observer, check the processes tab and see the processes with the most reductions.
How am I connecting?
To connect I am following a tutorial from a blog:
https://sgeos.github.io/elixir/erlang/observer/2016/09/16/elixir_erlang_running_otp_observer_remotely.html 1
Their instructions are as follows:
launch the app in the production machine with a cookie and a name
from local run: ssh user#public_ip "epmd -names" to get the name of the app and the port used
from local create a ssh tunnel to the remote machine: ssh -L 4369:user#public_ip:4369 -L 42877:user#public_ip:42877 user#public_ip (4369 is the epmd port by default, 42877 is the port of the app)
from local connect to the remote machine using the node's name: erl -name "user#app_name" -setcookie "mah_cookie" -hidden -run observer
Problem
And now in theory I should be able to use observer on the machine. Instead however I am greeted with the following error:
Protocol ‘inet_tcp’: register/listen error: epmd_close
So, after scouring the dark side of internet, I decided to use sudo journalctl -f to check all the logs of the machine and I found this:
channel 3: open failed: administratively prohibited: open failed
my_app_name sshd[8917]: error: connect_to flame#99.999.99.999: unknown host (Name or service not known)
/scripts/watchdog.sh")
my_app_name CRON[9985]: pam_unix(cron:session): session closed for user flame
Where:
erlang -name: my_app_name
machine user: flame
machine public ip: 99.999.99.999 (obviously not real)
so it tells me, unknown host ?? I am confused since 99.999.99.999 is the public IP of the machine itself!
Questions
What am I doing wrong?
I read that in older versions of erlang I can’t monitor a machine with observer if they are in different networks (which is the case, because I want to monitor this machine from my localhost) but I didn’t find any information regarding this in modern days.
If this is in fact impossible, what alternatives do I have?
Solution
After 3 days of non-stop searching, I finally found something that works.
To summarize I am putting it here everything I did.
All steps in local machine:
get the ports from the remote server:
> ssh remote-user#remote-ip "epmd -names"
epmd: up and running on port 4369 with data:
name super_duper_app at port 43175
create a ssh tunel with the ports:
ssh remote-user#remote-ip -L4369:localhost:4369 -L43175:localhost:43175
On another terminal in your local machine, run a iex terminal with the cookie the app in your remote server is using. Then connect to it and start observer:
iex --name observer#127.0.0.1 --cookie super_duper_cookie
Node.connect :"super_duper_app#127.0.0.1"
> true
:observer.start
With observer started, select the machine from the Nodes menu.
Possible setbacks
If you have tried this and it didn't work there are a few things you can check for:
Check if the EPMD port on your local machine is free, if not, kill the process using it and free it.
Check your ssh tunneling keys and configurations for permissions. As #Roberto Aloi pointed out this link can be useful: https://unix.stackexchange.com/questions/14160/ssh-tunneling-error-channel-1-open-failed-administratively-prohibited-open
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I am trying to connect to remote server via ssh but getting connection timeout.
I ran the following command
ssh testkamer#test.dommainname.com
and getting following result
ssh: connect to host testkamer#test.dommainname.com port 22: Connection timed out
but if try to connect on another remote server then I can login successfully.
So I think there is no problem in ssh and other person try to login with same login and password he can successfully login to server.
Please help me
Thanks.
Here are a couple of things that could be preventing you from connecting to your Linode instance:
DNS problem: if the computer that you're using to connect to your
remote server isn't resolving test.kameronderdehamer.nl properly
then you won't be able to reach your host. Try to connect using the
public IP address assigned to your Linode and see if it works (e.g.
ssh user#123.123.123.123). If you can connect using the public IP
but not using the hostname that would confirm that you're having
some problem with domain name resolution.
Network issues: there
might be some network issues preventing you from establishing a
connection to your server. For example, there may be a misconfigured
router in the path between you and your host, or you may be
experiencing packet loss. While this is not frequent, it has
happenned to me several times with Linode and can be very annoying.
It could be a good idea to check this just in case. You can have a look
at Diagnosing network issues with MTR (from the Linode
library).
That error message means the server to which you are connecting does not reply to SSH connection attempts on port 22. There are three possible reasons for that:
You're not running an SSH server on the machine. You'll need to install it to be able to ssh to it.
You are running an SSH server on that machine, but on a different port. You need to figure out on which port it is running; say it's on port 1234, you then run ssh -p 1234 hostname.
You are running an SSH server on that machine, and it does use the port on which you are trying to connect, but the machine has a firewall that does not allow you to connect to it. You'll need to figure out how to change the firewall, or maybe you need to ssh from a different host to be allowed in.
EDIT: as (correctly) pointed out in the comments, the third is certainly the case; the other two would result in the server sending a TCP "reset" package back upon the client's connection attempt, resulting in a "connection refused" error message, rather than the timeout you're getting. The other two might also be the case, but you need to fix the third first before you can move on.
I got this error and found that I don't have my SSH port (non standard number) whitelisted in config server firewall.
Just adding this here because it worked for me. Without changing any settings (to my knowledge), I was no longer able to access my AWS EC2 instance with: ssh -i /path/to/key/key_name.pem admin#ecx-x-x-xxx-xx.eu-west-2.compute.amazonaws.com
It turned out I needed to add a rule for inbound SSH traffic, as explained here by AWS. For Port range 22, I added 0.0.0.0/0, which allows all IPv4 addresses to access the instance using SSH.
Note that making the instance accessible to all IPv4 addresses is a security risk; it is acceptable for a short time in a test environment, but you'll likely need a longer term solution.
If you are on Public Network, Firewall will block all incoming connections by default. check your firewall settings or use private network to SSL
The possibility could be, the SSH might not be enabled on your server/system.
Check sudo systemctl status ssh is Active or not.
If it's not active, try installing with the help of these commands
sudo apt update
sudo apt install openssh-server
Now try to access the server/system with following command
ssh username#ip_address
This happens because of firewall connection.
Reset your firewall connection from your hosting website.
It will start working.
After connecting to the server again add this to your (ufw) security
sudo ufw allow 22/tcp
There can be many possible reasons for this failure.
Some are listed above. I faced the same issue, it is very hard to find the root cause of the failure.
I will recommend you to check the session timeout for shh from ssh_config file.
Try to increase the session timeout and see if it fails again
My VPN connection was not enabled. I was trying all possible way to open up the Firwall and Ports until I realized, I am working from home and my VPN connection was down.
But yes, Firewall and ssh configurations can be a reason.
Try connecting to a vpn, if possible. That was the reason I was facing problem.
Tip: if you're using an ec2 machine, try rebooting it. This worked for me the other day :)
I had this issue while trying to ssh into a local nextcloud server from my Mac.
I had no issues ssh-ing in once, but if I tried to have more than one concurrent connection, it would hang until it timed out.
Note, I was sshing to my user#public-ip-address.
I realized the second connection only didn't work when I tried to ssh into it when on the same network, ie my home network
Furthermore, when I tried ssh user#server-domain it worked!
The end fix was to use ssh user#server-domain rather than ssh user#public-ip
I have experienced a couple of nasty issues that lead to these errors, and these are different from everyone else's answer here:
Wrong folder access rights. You need to have specific directory permissions on you ssh folders and files.
a. The .ssh directory permissions should be 700 (drwx------).
b. The public key (.pub file) should be 644 (-rw-r--r--).
c. The private key (id_rsa) on the client host, and the authorized_keys file on the server, should be 600 (-rw-------).
Nasty docker network configuration. This just happened to me on an AWS EC2 instance. It turned out that I had a docker network with an ip range that interfered with the ssh access granted by the security group and VPC. The docker network's range was e.g. 192.168.176.0/20 (i.e. a range from 192.168.176.1->192.168.191.254), whereas the security group had a range of 192.168.179.0/24; interfering with the SSH access.
I had this error when trying to SSH into my Raspberry pi from my MBP via bash terminal. My RPI was connected to the network via wifi/wlan0 and this IP had been changed upon restart by my routers DHCP.
Check IP being used to login via SSH is correct. Re-check IP of device being SSH'd into (in my case the RPI), which can be checked using hostname -I
Confirm/amend SSH login credentials on "guest" device (in my case the MBP) and it worked fine in my attempt.
I faced a similar issue. I checked for the below:
if ssh is not installed on your machine, you will have to install it firstly. (You will get a message saying ssh is not recognized as a command).
Port 22 is open or not on the server you are trying to ssh.
If the control of remote server is in your hands and you have permissions, try to disable firewall on it.
Try to ssh again.
If port is not an issue then you would have to check for firewall settings as it is the one that is blocking your connection.
For me too it was a firewall issue between my machine and remote server.I disabled the firewall on the remote server and I was able to make a connection using ssh.
my main machine is windows 10 and I have CEntOS 7 VBox
Search in your main machine for "known_hosts"
usually, known_host location in windows in "user/.ssh/known_host"
open it using notepad and delete the line where your centos vbox ip
then try connect in your terminal
in mac os user you can find known_hosts in "~/.ssh/known_hosts"
Make sure to ask the admin to authorize your device.
On Linux run:
sudo zerotier-cli listnetworks
if it returns status ACCESS DENIED ask the admin to authorize your node. This is mentioned here.
https://discuss.zerotier.com/t/solved-cant-join-network/1919
This issue is also caused if the Dynamic Host Configuration Protocol is not set-up properly.
To solve this first check if your IP Address is configured using
ping ipaddress,
If there is no packet loss and the IP Address is working fine try any other solution. If there is no response and you have 100% packet loss, it means that your IP Address is not working and not configured.
Now configure your IP Address using,
sudo dhclient -v devicename
To check your device you can use the 'ip a' command
For eg. My device was usb0 since I had connected the device through usb
This will configure an IP Address automatically and you can even see which one is configured. You can again check with the 'ip a' command to confirm.
This may be very case specific and work in some cases only but
check to see if you were previously connecting through some VPN software/application.
Try connecting again to the VPN. Worked in my case.
This happened to me after enabling port 22 with "sudo ufw allow ssh". Before that, I was getting a refusal from my machine when entering with ssh from another one. After enabling it, I thought it would work, but instead it showed the message "connection timed out". As I had just installed Ubuntu with the option of installing basic functions alongside, I checked whether I had the openssh-server with the command sudo apt list --installed | grep openssh-server. It turned out that Ubuntu had installed by defect the openssh-client instead. I uninstalled it and installed the openssh-server following the basic commands:
sudo apt-get purge openssh-client
sudo apt update
sudo apt install openssh-server
After that, a simple "sudo ufw allow ssh" worked perfectly and I was finally able to access the machine with an ssh command.
What worked for me was that i went to my security group and reset my IP and it worked
Here are some considerations which i took to resolve a similar issue that I had:
Port 22
IGW (Internet Gateway)
VPC
Scene 1> This is for port 22 not enabled with right configurations. If the port is set to custom or myip, the probable scene is this won't work.
Scene 2> When you delete the internet gateway, the network is created and the instance will be functional too, but the routing from the internet will not work. Hence make sure that if there is a VPC, it has an Internet Gateway attached.
Scene 3> Check the VPC for the subnet associations and routing table entries. This might probably tell you the cause. I found one in this kind of troubleshooting. The route used to land up in a "blackhole" (shows up in the route table section of the console). To fix this I had to check and find out my internet gateway and found the issue with the IGW.
Moral of the story: always trace backward in the network!
In my case I'm on windows, I reset my firewall settings, and it fixed
If you get any error check the basic a version control request with ssh -V and If it is not installed, install it with the sudo apt-get install openssh-server command.
Check your virtual machine ssh connection with sudo service ssh status at console.
Check "Active" rows and if write a inactive(dead) the console write sudo service ssh start
Result: Now you can check your connection with sudo service ssh status command and send ssh connection request.
Reset the firewall and reboot your VPS from your hosting service, it will start working perfectly fine
check whether accidentally you have deleted the default vpc or default subnets ,while creating your own vpc and subnets.
I have done this mistake while creating vpc, hence got this error while connecting via ssh.
alos check whether u have attched IGW to public subnets.
Its not complicated.
First, go disable your firewall(USE YOUR CONTROL PANEL)after you check if your openssh is active.
Disable firewall, then use putty or any alternative to basically disable using this command sudo ufw disable
try now
Update the security group of that instance. Your local IP must have updated. Every time it’s IP flips. You will have to go update the Security group.
How would I access a webserver behind a firewall? I'm developing an application for this webserver which is not yet open to the public.
Someone walked me through this before, so I know it can be done. However, it has been about four months and I haven't been able to do it again.
I'm using Putty to connect to the remote machine. From that machine I can open the site http://dev.server.address:83 using Firefox. However, I want to be able to open http://localhost:80 on my machine to see the same page.
I'm using the server address and port 83 for the "source port"
I'm using localhost:80 for the "destination port"
You need to enter "80" into Source port and dev.server.address:83 to Destination.
[And don't forget to click the "Add" button before you leave the configuration screen. If you don't click that, PuTTY doesn't actually create a tunnel. I fell for that gotcha quite a few times myself]
Have you tried using 127.0.0.1:80 instead of localhost:80? I don't use PuTTY, but when I use SSH on my machine, I have to specify 127.0.0.1 instead of localhost.
Do you have a webserver running on your local machine? If that is listening on port 80 http://localhost:80 wont work. Alternatively try mapping the source to a different port (12345 for eg.) and then try http://localhost:12345 in your browser.
On Linux you can also make it happen with:
$ ssh -f -R 83:localhost:80 user#dev.server.address
Provided that you have an SSH account named "user".