I have to login to a server from a remote server. I am able to login to remote server using phpseclib. After that I am able to login to next server from that but next command executes on firt server and not the second server. For example:
Login to server1.example.com via SSH
Login to remote-server.example.com using internal script from server1.
Execute 'ls'.
ls returns output from server1 rather remote-server.
Are you absolutely sure your script on server1 actually logs into remote-server (and does not immediately log out)? The only explanation I can think of is that the "ls" command is not really run on the remote server. If you share the script and exact commands, that could help figure it out. (Output of "script" from the whole exchange might also be helpful.)
Something like the following might also work for you:
ssh server1.example.com ssh remote-server.example.com ls
Depending on your remote command, you might also do something like:
ssh server1.example.com "ssh remote-server.example.com ls"
(The latter might be needed if there are, e.g., redirects involved that could otherwise be interpreted by your local shell.)
As you use phpseclib, that might handle the first ssh in the examples above. So you might perhaps use something like:
$ssh->exec("ssh remote-server.example.com ls")
Or if you are using public key authentication for the second step, maybe:
$ssh->exec("ssh -i ~/.ssh/keyfile remote-server.example.com ls")
There's a quick summary of how to run commands remotely with ssh at https://www.ssh.com/ssh/command/
Related
I have taken over a project that has an AWS ec2 elasticbeanstalk instance running a socket.io server.
I have logged in via and done the following steps.
SSH in
cd /var directory.
ls > account app cache db elasticbeanstalk empty games kerberos lib local lock log mail nis opt preserve run spool tmp www yp
I can't see to find the socket server code? Nor the logs for the socket server?
I am not sure where they would be located.
There are myriad methods to get code on to a server and to run it. Without any information about the code or the OS or anything else, assuming its a Linux based OS, if I’m looking for something and know what it is, I can usually find it by searching for a string that I know I will find inside at least one of the files on the server.
In this case, since its a socket.io, I’d search for socket.io:
grep -rnw '/' -e 'socket.io'
The result will show me all files, including the full path, that contain “socket.io”, and you should be able to determine where the code is pretty quickly.
I have a C++ module whose basic work is to check if a directory exists in the remote machine or not. I am using the system() call for the same .
ssh user#remote-machine [ -d /remote_dir/test]
This works fine giving the result, but intermittently the test fails (the test directory is always there).
Now what might the reason and how to check this.
The test succeeds but gets failure reason (system() call unreliable).
Might be some network issue between the systems. If yes how to check this?
Thanks in advance.
SKP
Make sure that your connection is ok for specified ssh port:
$ telnet remote-machine 22
It should show connection messages, otherwise nothing (means that SSH not allowed to connect by IP firwall on local or remote machine).
If not first, than check credentials to start the "system()" command. Because if you use system() call from the console from user "user1", but module started from user "user2" in the Linux system. In this case credentials to access remote server without password will fail because you made, in example, ssh keys for "user1" and not for "user2" - check it in the /home/(username)/.ssh. For debug if it so, use
...system('ls -l ~/.ssh');
And if no files then you should make connection keys for user who starts this module.
I want to establish an API server with a load balancer. I will use one machine as the master which will assign tasks in a round robin manner to 2 slave machines. All machines are hosted in AWS.
In order to process the request, I need to run a python script. When the master receives the request, it can trigger the command on one of the slaves using ssh but this adds an extra couple of seconds delay to the processing time.
Is there a way to reduce/remove the ssh delay?
Not sure if you have something implemented or you just collect the thoughts.
The basic use case is described on wikibooks, but the easiest is to set up public key authentication and ssh_config (config for machine2 would be almost the same):
Host machine1
HostName machine1.example.org
ControlPath ~/.ssh/controlmasters/%r#%h:%p
ControlMaster auto
ControlPersist yes
IdentityFile ~/.ssh/id_rsa-something
And then call the remote script like this:
ssh machine1 ./remote_script.py
First ssh call will initiate the connection (and will take a bit longer), every other script call will use the existing connection and will be almost immediate.
If you are using Python, the similar behaviour you can achieve using paramiko or even ansible if you want to step one level up (but really depends on use case).
My application use database which is on another server. To increase security, access to db server was restricted only for specified production servers.
However sometimes I need to have access to this db, when running development environment from my localhost.
For now a simply run in another console before running server:
ssh tunnel#server-with-access-to-db.com -L 12345:localhost:3306
..which works great, however I need to remember to do that.
I am wondering how to write custom runserver which will establish tunnel automatically, and what is important, will close that tunnel after server will be shut down.
I know that in the future VPN will be much better, however it is not possible for now.
I will be grateful for any suggestions.
FYI: one part of writing custom runserver command is extending it. You can use this example to do so.
I am wondering if someone can provide me with a couple c++ functions that would allow me to send and receive data over a telnet port.
I've also heard that I can create a program, and have it run via SSH, this would be preferred just because of the security benefits of SSH, are there any samples out there?
Update:
What I want to do, is create a console program users could use remotely via SSH or telnet. I am a C++ programmer.
Update 2: I know I was vague, I am creating an inventory system that I want to be accessible to our employees via SSH or telnet. I will be using sockets, and will often display data to the user via (telnet or through ssh) and accept input from them. I will have to implement sockets, and send data and receive data I know, is there a library for this?
I am not quite sure what you are asking here.
You can execute a remote program via:
ssh <user>#<machine> "<command>"
(Provided you have prepared a passphrase-less pubkey authentication; you'd be asked for a password / passphrase otherwise. The very first invokation will also require user input as SSH wants to verify the fingerprint of the remote machine.)
You could then capture the output of that command line (which is equivalent to the output of the remote command, unless ssh itself belches an error) via the usual means.
I seriously dont believe you want to implement telnet and SSH protocol all by your handwritten code!! That would be too difficult for you.
What I think you want to do is to "Run a command remotely". is it?
If yes then you you would need to execute the command as told by DevSolar but you will need to generate SSH keygen to be installed so that it doesnt ask for password at the prompt.
Else write an expect script.