I have a powershell script that keeps closing ```ssh jumpbox_user#jumpbox_ip -p 22 -L port:server_address:port -i '~/.ssh/id_rsa' -N
The issue I have is that the tunnel will start but will then, randomly, it will close. I have this issue no matter how I start the SSH tunnel. I get the feeling that it has something to do, potentially, with my home internet? I don't seem to have this issue at work or at other locations. I've purchased a new router and a new modem to no effect, is there a way to check what is going wrong???
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When I'm teleworking, I need to access some internal web servers. I use ssh -f -N -D 4000 someserver.mywork.com on my home computer to setup local dynamic port forwarding. Then, I configure my web browser to use localhost port 4000 as a SOCKS host, and everything works great, even with HTTPS.
The problem is that the proxy stops working every couple of days. When this happens, the ssh process prints messages like the following:
accept: Too many open files
In this scenario, I have to kill the ssh process and restart it in order to get it working again. Based on my research into this error message, I could increase the limit on the number of open files, but that doesn't seem like a permanent or an ideal solution.
I was hoping autossh might be able to monitor the connection and restart it automatically. Is that possible?
I have tried the following command:
autossh -f -M 0 -N -D 4000 someserver.mywork.com
But it didn't work. The proxy stopped working, and autossh did not restart it. Any suggestions or alternative solutions to automatically restarting my ssh proxy?
SSH has been working fine for the last few weeks since I got my new PC. I've had no problems but today I started getting:
ssh: connect to host github.com port 22: resource temporarily unavailable
I did some googling and found that there is a common issue with WSL which sometimes causes this, but I'm unable to SSH from my bash shell, or from cmd/powershell.
This is the part that confuses me, if I do: ssh -T git#192.30.253.113 I am prompted for the password to my key, it successfully authenticates and responds with "Hi alexmk92! You've successfully authenticated".
Great, that at least proves that my firewall isn't blocking SSH on port 22. But why does git#github.com throw the resource failed error? My initial thought is that this could be a DNS problem.
So I tried to configure my network adapter to use Google's DNS server (8.8.8.8 and 8.8.4.4) I even configured the IPV6 DNS servers just in case. Following this I did an ipconfig /flushdns, attempted to connect via git#github.com again and BAM the same result, however git#192.30.253.113 still works.
I'm guessing another potential cause is that github.com is behind a load balancer and one of the IP's on the cluster could be black-listed somewhere on my machine? I'm just pulling guesses out of thin air now, any help would be greatly appreciated, this is driving me insane.
After some further Googling it turned out that my machine did not have a hosts entry for github.com and it was unable to automatically resolve it.
In Windows Subsystem for Linux I created a ssh config file
touch ~/.ssh/config
(for some reason the base distro of Ubuntu 18.04 on the windows marketplace didn't have one) I then had to make sure the file permissions were correct:
chmod 755 ~/.ssh/config
Once the file was created, I edited it with
sudo nano ~/.ssh/config
and added github.com as a Host.
Host github.com
Hostname ssh.github.com
Port 22
Upon saving, I ran
sudo /etc/init.d/ssh restart
and attempted
ssh -T git#github.com
Everything now seems to be working.
In my case my ISP did not allow ssh, so it was not working from cmd and wsl both. Got around it using vpn
To have successful SSH connection to Github, SSH key has to be import into Github
Open Git bash or Terminal
Run the command ssh-keygen
Choose all default option
A private and a public key gets generated in the folder * < user_home>/.ssh/*
Login to Github.com
Navigate to account settings
Choose item "SSH and GPG Keys" from the side navigation bar
click added new SSh key
Copy and save public key content from * < user_home>/.ssh/id_rsa.pub *
I want to write a script that connects via ssh (ssh user#host) and runs watch who there.
Normally I would just do
ssh user#host
# I am now on the other machine
watch who
But a spript would wait until the first command is done and would start the second one. So my next try is
ssh user#host watch who
but I get an error ($? is 1) and a message:
"Error opening terminal: unknown"
ssh user#host who works just fine though. So how could I approach this?
(My real application is not to watching the users but watching the print queue, but the problem seems to be the same and I guessed that more people are familiear with who then with lpstat)
The watch needs a PTY, which is not allocated when you add a command to ssh. Use
ssh -t user#host "watch who"
I often use an ssh tunnel. I open up one terminal to create the tunnel (e.g. ssh -L 1111:servera:2222 user#serverb). Then I open a new terminal to do my work. Is there a way to establish the tunnel in a terminal and somehow put it in the background so I don't need to open up a new terminal? I tried putting "&" at the end, but that didn't do the trick. The tunnel went into the background before I could enter the password. Then I did fg, entered the password and I was stuck in the ssh session.
I know one possible solution would be to use screen or tmux or something like that. Is there a simple solution I'm missing?
There is the -f and -N options exactly for that:
-f Requests ssh to go to background just before command execution. This is useful if
ssh is going to ask for passwords or passphrases, but the user wants it in the
background. This implies -n. The recommended way to start X11 programs at a remote
site is with something like ssh -f host xterm.
If the ExitOnForwardFailure configuration option is set to ``yes'', then a client
started with -f will wait for all remote port forwards to be successfully established
before placing itself in the background.
-N Do not execute a remote command. This is useful for just forwarding ports
(protocol version 2 only).
So the full command would be ssh -fNL 1111:servera:2222 user#serverb.
A way to prevent ssh asking for the password would also be to use SSH public keys for authentication with an agent that either saves the password or prompts it using an external graphical program such as pinentry.
It might also be useful for you to look into autossh, which will reconnect your SSH automatically if the connection drops.
I have a strange SSH problem.
If I run this
ssh user#remote 'md5sum file.txt'
I get back the result as expected, but if I run this
ssh user#remote 'cat file.txt'
then it just sits there.
I'll attribute this problems to bad network connection. I've started using Mosh and is works magnitudes better than ssh.