I try to commit to my SVN while being in a restricted network where most ports are blocked.
I have a linux server with the ssh port on 21 which seems to be unlocked (anonymous test ftp works), but whenever I try to establish a connection using PuTTy, the window stays black and nothing happens.
I can connect using a web ssh client. What could be the reason I can't connect using PuTTy?
Related
I was updating the ssh port of an Oracle Cloud Infrastructure machine
I changed /etc/ssh/sshd_config
The port was
#Port 22
I changed it to
Port 40531
Then
restarted the sshd service systemctl restart sshd
open the port on the OCI Web
however, now I cannot connect.
ssh -vvv -p 40531 -i ~/.ssh/vm.key opc#129.xxx.xxx.xxx
OpenSSH_8.2p1, OpenSSL 1.1.1e 17 Mar 2020
debug1: Reading configuration data /etc/ssh/ssh_config
debug2: resolve_canonicalize: hostname 129.xxx.xxx.xxx is address
debug2: ssh_connect_direct
debug1: Connecting to 129.xxx.xxx.xxx [129.xxx.xxx.xxx] port 40531.
debug1: connect to address 129.xxx.xxx.xxx port 40531: Connection timed out
ssh: connect to host 129.xxx.xxx.xxx port 40531: Connection timed out
I saw a Cloud Shell but I'm not sure if it can be used to connect to the machine to perform maintenance tasks
Is there a way to connect to the VM from the web oci interface to fix the ssh issues?
I used to use a VPS service that has a web console from which you can enter to fix problems like this
is there something like this in OCI?
Note:
SELinux was disabled on the machine
if you are about to do this on your machine, remember to update the SELinux configuration prior restart the sshd service or you will be locked out, another option is to disable SELinux totally (this is what I did)
The changes above described worked well, the only thing that was causing issues on my side
(I don't really know why) is that I was connected from a VPN
After I disconnected the VPN and tried to connected again it worked
Update:
I figured out why the ssh using a different port was not working. The VPN I use is a corporate VPN which has very strict inbound and outbound rules, The VPN outbound rules were blocked by the TCP on port 40xxx.
Update:
if you are struggling with a VM you can connect using the below instruction
Creating the Instance Console Connection
Before you can connect to the serial console or VNC console, you need to create the instance console connection.
To create the console connection for an instance
Open the navigation menu. Under Core Infrastructure, go to Compute and click Instances.
Click the instance that you're interested in.
Under Resources, click Console Connection.
Click Create Console Connection.
Upload the public key (.pub) portion for the SSH key. You can browse to a public key file on your computer or paste your public key into the text box.
Click Create Console Connection.
When the console connection has been created and is available, the state changes to Active.
Thanks to #bmuthuv for the info
You can connect to Serial Console of the VM where you could get access to GRUB Menu during a Reboot operation. You can subsequently use typical Linux commands to get to Shell from Grub. You can subsequently undo anything you would like to.
Serial Console connection can be created on OCI Web Console in the Instance's page.
I am ssh-ing onto a remote desktop. Since I have to connect over the internet, I have exposed the ssh port (22) on the remote side using ngrok, and everything is working great. I connect to the desktop using the command
ssh username#2.tcp.ngrok.io -p portno
where I get the portno from the remote side, when I start the ngrok service from the line that says
Forwarding tcp://2.tcp.ngrok.io:portno -> localhost:22
However, everytime I start a new ngrok session on the remote side, a new portno is generated. Now, unless I have a secondary connection open (typically using teamviewer), I would not be able to know what that port number is.
How can I start the ngrok service with a fixed portno. This is because I want to have the ngrok service on startup as I would have to restart my remote desktop a couple of times and still want to connect to the desktop using ssh.
Thanks.
You'll need to reserve a TCP address on ngrok, which will give you a fixed address.
To associate a tunnel with a reserved TCP address, you should include the remote-addr option in your ngrok config when starting the tunnel.
An example from the docs: ngrok tcp --region=us --remote-addr 1.tcp.ngrok.io:20301 22
I want to connect to a remote server (host1) that accessible only from it's private network.
Another server (host2) is accessible from the Internet.
I opened a tunnel to host2 using PuTTY and tested it's working with Firefox (also checked that I got different IP address).
How can I connect to host1 using the tunnel I created?
I tried to configure proxy (to the tunnel I created - localhost) in PuTTY but it's not working.
The error I got: "Server unexpectedly closed network connection"
Pay attention that the host is the computer name in the network.
You connect to the local tunnel end directly, no "proxy" setting is needed.
This typically means that you use "localhost" as a Host Name. And a port according to your tunnel configuration.
See my guide for tunneling SFTP/SCP session. It's for WinSCP, but just use PuTTY instead of WinSCP in section Connecting through the tunnel.
I need to connect (in rdp ) to a machine (let's call it #1) in my college network ( I have the internal IP of it ) , I also have access the to Linux server machine in the same network in ssh , that I can use to access the #1 ,
I'm using putty, can someone please explain to me how I can connect to it ?
[My laptop] --->[Linux server] --->[windows machine] in rdp
Thank you,
Let's assume the following:
Linux Server - gate.college-server.com:22 (SSH listens on port 22)
Internal Server - internal.college-server.com:3389 (RDP listens on port 3389)
RDP connection will be on localhost:3399 (the port should be opened)
How to configure the SSH tunnel via Putty with RDP forwarding:
Open Putty and in the Session enter the connection info for the Linux Server
Go to branch > Connection > SSH > Tunnels
Choose Local and Auto
in the Source Port enter 3399, and in the Destination - the connection info of the internal machine in the format: hostname:port.
Click Add
you will see entry in the Forwarded ports section, something like:
4L3399 internal.college-server.com:3389
Save your connection and it's ready to use.
Next, start the a PuTTy Session with the Saved Connection and after you login successfully
to the remote server gate.college-server.com:22, you can start your Windows RDP client.
Connect with it to localhost:3399 and use the RDP credentials for internal.college-server.com:3389
I am currently trying to work out how to SSH to servers behind firewalls that deny all incoming connections. The servers can SSH out, so I am wondering if there is a way to get the server behind the firewall to create an SSH tunnel to my workstation, then allow my workstation to send commands back to the server through it?
I have looked into tunneling / reverse tunneling, but these appear to be port forwarding solutions, which will not work as the firewall denies all connections on all ports.
Ideally, I would like to do this in Ruby (using the Net::SSH gem), such that instead of opening a new connection like:
Net::SSH.start('host', 'user', :password => "password")
I could somehow bind to an existing tunnel.
Thanks!
This is fairly simple if you have control over the server. I'll give the command-line version, and you can work that into any framework you like:
server$ ssh -R 9091:localhost:22 client.example.egg
client$ ssh -p 9091 localhost
The server establishes a connection to the client first which starts listening on the "R"emote end (i.e. the client) on port 9091 (something I just made up), and forwards those connections to localhost:22, i.e. to the ssh server on itself.
The client then just needs to connect to its own local port 9091, which is transparently forwarded to the server's ssh server.
This will usually wreak havoc to your public key checking (and adherent security!), because the client's ssh client doesn't know that localhost:9091 is the same as server:22. If your client is Putty, then you have an option to provide the "real" server name somewhere so that the credentials can be looked up properly.
Unless you can create (and maintain) a tunnel out from the host you're trying to connect to first (which would allow you then to connect through that tunnel), no you can't. That's the point of a firewall: prevent unauthorised access to a network.
However the firewall shouldn't block a tunnel, although it depends exactly how the tunnel's managed. A port-forwarding tunnel set up using ssh's tunneling features would subvert the firewall. However it may also get you in trouble with the administrator of the remote network.
So ultimately, you'd need to speak to the network administrator to get the firewall rules relaxed in order to do it without needing to tunnel, or at least get authorisation to have a tunnel.