Secure Shell (SSH) is a protocol primarily for encrypted shell connections. This tag is also used for questions about sshd and openssh, the two standard applications for using SSH.

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10
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2answers
7k views

How can I close SSH tunnel gracefully?

I have open tunnel with ssh -2 -N -L 5001:localhost:1019 eonil@test.local The tunnel is working good, but I have to Ctrl+C or Ctrl+D to force quit the tunnel. How can I close the tunnel gracefully?
7
votes
8answers
23k views

Is it possible to prevent SCP while still allowing SSH access?

Using Solaris and Linux servers and OpenSSH, is it possible to prevent users from copying files using "scp" while still allowing shell access with "ssh"? I realize that 'ssh $server "cat file" ' type ...
5
votes
2answers
2k views

Easy multi-level authentication for sudo

I have a FreeBSD server with password-based SSH enabled. I would like to enable sudo, but I do not want a potential attacker to be one password away from root access. My current solution is logging ...
3
votes
11answers
863 views

Ubuntu Server SSH

I have a server with ubuntu. I do work on it over SSH. I had a problem with brute force attempts over port 22. I changed the port and I assumed it fixed the brute force problem. Am I right or are the ...
17
votes
4answers
7k views

Is it possible to get OpenSSH to log the public key that was used in authentication?

I have a production system where several different people are allowed to log in to a single account - the account is for the application and not for the person as we don't have personal accounts on ...
14
votes
3answers
2k views

Inline SSH command

Is it possible to do a simple inline style SSH command, for example: ssh foo@bar.com { cd foo/bar && rm *.foobar }
10
votes
2answers
3k views

SSH MOTD per user

I want to display banner (welcome message) for SSH users with a specific welcome message for each user.
9
votes
3answers
25k views

Rsync command issues, owner and group permissions doesn´t change

I´m trying to set owner and group via rsync and it doesn't seem to be working. This is the command: sudo rsync -rlptDvz --owner=cmsseren --group=cmsseren /home/serena/public_html/ -e ssh root@ip:/...
9
votes
5answers
4k views

Stop ssh client from offering all the public keys it can find?

Like most sysadmins I use openssh all the time. I have about a dozen ssh keys, I like to have a different ssh key for each host. However this causes a problem when I am connecting to a host for the ...
9
votes
4answers
7k views

Transfer files via SSH

I want to use file transfer via SSH on some scripts. I've read it's possible to tar over ssh. Where should I start reading?
9
votes
3answers
4k views

OpenSSH with public keys from database

Is it possible to fetch the public keys from a database instead of the authorized_keys file? I would like to use such a setup to manage ssh access to things like git repositories for multiple users ...
8
votes
2answers
16k views

SSH tunnel over multi hops using putty

I have a situation where I want to connect to a Linux machine running VNC (lets call it VNCServer) which is behind two consecutive Linux machines i.e., to ssh into the VNCServer, I have to ssh into ...
6
votes
1answer
1k views

Adding port forwardings programmatically on a ControlMaster SSH session

I just found out about the ControlMaster/ControlPath feature of OpenSSH, which allows you to use a single SSH connection to run multiple terminals. As I often use SSH to use port forwarding to get ...
5
votes
5answers
7k views

How can I disconnect ssh users, or limit the number of ssh logins?

I have an application that is using ssh to authenticate. Due to a variety of regulations (HIPAA, etc) users can only be logged in for a certain amount of time, and they can only be logged in once. I ...
4
votes
3answers
9k views

How can I enable X11 forwarding to a Debian server box?

I want to connect to a server with SSH (a Debian installation in a VMware image). On that server I want to call gitk a repository viewer for git. What do I need to do to make this work?
1
vote
2answers
4k views

ssh remote command-fu

I am trying to do a remote backup from behind a firewall. It is really no problem to break this out into its own script that gets called in crontab, but that isn't any fun! What I am trying to do ...
21
votes
5answers
24k views

Ssh, run a command on login, and then Stay Logged In?

I tried this with expect, but it didn't work: it closed the connection at the end. Can we run a script via ssh which will log into remote machines, run a command, and not disconnect? So ssh in a ...
17
votes
5answers
22k views

Force SSH to use a specific shell

Is there any way to force SSH to use a particular shell on the remote end, regardless of what the user's default shell is? I've tried solutions akin to: ssh host.domain.com /bin/bash -c 'complicated,...
15
votes
6answers
11k views

Is there a way to avoid SSH typing delay?

Can I tell SSH to send the data only after pressing enter or tab, and not after each individual keypress?
12
votes
1answer
4k views

Only allow password authentication to SSH server from internal network

I have an OpenSSH 5.9p1 server running on Ubuntu Precise 12.04 which accepts connections from both the internal network and the Internet. I'd like to require public key authentication for connections ...
11
votes
2answers
11k views

Authentication Order with SSH

When I login via ssh with -v I see that ssh is authenticating the following way debug1: Authentications that can continue: publickey,gssapi-with-mic,password,hostbased I would like to change the ...
9
votes
2answers
19k views

SFTP fatal bad ownership or modes for chroot directory ubuntu 12.04

I just set up my SFTP server and it works fine when I use it from my first user account. I wanted to add a user which we will call 'magnarp'. At first I did like this in sshd_config: Subsystem sftp ...
8
votes
3answers
4k views

Restricting the network access of Docker container

I'm in the process of creating an SFTP only Docker container, one that will be used by multiple people for the sole purpose of uploading and managing files in their own chrooted Environment. On paper,...
8
votes
1answer
2k views

SSH passphrase remembered in MacOSX Snow Leopard

I am facing a very strange situation with Snow Leopard. I have a Linux server, configured to accept an ssh connection authenticated only through RSA key. No password. On my laptop I correctly deployed ...
8
votes
7answers
13k views

Can't get detached screen to resume

I use putty and have an unreliable wireless connection, so I use screen to keep my work going. Often I'll get disconnected, and then I can't reattach my screen. I'll run screen -D -RR and it will just ...
8
votes
5answers
26k views

Disable usage of console-kit-daemon in Ubuntu

I administrate several Ubuntu 9.04 servers, and everytime I log in, I get the Landscape utility printout with server stats, etc. I really don't need this and it slows down my logins considerably. ...
7
votes
6answers
8k views

lots of failed SSH login attempts - should I be concerned? [duplicate]

Possible Duplicate: Is it worth the effort to block failed login attempts Is it normal to get hundreds of break-in attempts per day? I'm managing a number of completely different root ...
6
votes
2answers
17k views

execute su -c over ssh

I am trying to check the BIOS version of a server over SSH, a command that requires root privileges: ssh remote-server su -c dmidecode but this of course fails with the error: standard in must ...
5
votes
4answers
6k views

Is it possible to connect a EC2 Linux instance via ssh without the key pair?

I can connect to my EC2 Linux instance via ssh using the key pair (*.pem). Is it somehow possible to connect it with ssh with out the pem file?
4
votes
2answers
2k views

Remote server hangs, gets stuck. How to debug?

I have an vps running on VmWare ESX with Ubuntu 8.04 LTS. It has been running smoothly for the past 3 months, however recently we've notices two strange bugs. a. The server hangs, today was second ...
4
votes
2answers
5k views

How to display SSH banner at login, but only for password authentication

I have a warning message that is displayed to a user after they enter their username to log in to our Linux servers. I only want to display this message for password authentications, and not when ...
4
votes
3answers
4k views

ssh “WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!”

I've been using ssh to log-in to a remote server I rent for several years. Last week I got a message from them saying they upgraded my account and server. Now when I go to login, I get this message ...
3
votes
4answers
3k views

Wordpress can't find ssh public and private key pair

My server configuration is as follows: CentOS 5.8 (final) running Nginx. I am using the SSH2 feature of Wordpress's plugin installer. I have installed lib2ssh and it is working (Wordpress is ...
1
vote
2answers
4k views

How does one determine active SSH and SAMBA connection counts?

I have a server that I use infrequently, so I'd like to cron a job to shutdown daily if no users are logged in via SSH and SAMBA shares. How can I determine how many active SSH connections there are, ...
15
votes
3answers
1k views

Cannot reattach to a screen session after SSH connection was dropped

I have previously reattached to a long-running screen session with screen -dr control. However, sometimes this command will not reattach to the screen and instead hang forever (10+ minutes after which ...
13
votes
3answers
5k views

Use .bashrc without breaking sftp

My problem is that I need to set a few variables, and output a few lines every time I login to the ssh shell, and at the same time I have to be able to use sftp to tarnsfer files via Filezilla. Now, ...
12
votes
8answers
23k views

Why can't I ssh into my new EC2 Instance?

I created a new instance (tiny, 64 bit AMI linux from Amazon) Created a new key pair called "mir". I downloaded mir.pem and put it in my ~/.ssh folder. I even did ssh-add mir.pem. Then I tried to ...
9
votes
3answers
16k views

Allow scp/ssh for www-data user

I am on Amazon EC2 using Ubuntu 10.04.2 My web folder is owned by www-data so I want to be able to log into my server as www-data for ssh and scp. Thanks! Adding the line to my /etc/ssh/sshd_config ...
9
votes
4answers
20k views

In Fail2Ban, How to Change the SSH port number?

In my server, the ssh port is not the standard 22. I have set a different one. If I setup fail2ban, will it be able to detect that port? How can I tell it to check that port rather than port 22? The ...
8
votes
3answers
2k views

Is SSH logging capabilities equivalent to su logging for private/public key authentication?

Here at work, we have a non-root shared login account on UNIX that is used to admin a particular application. The policy is to not allow direct logins to the shared account; you must login as yourself ...
8
votes
5answers
4k views

SSH session drops - Does the command continue executing?

If I was running a command before the SSH connection was dropped, will the command continue executing?
8
votes
3answers
3k views

What exactly does ssh send when performing key negotiation?

When explicitly specifying identity file to ssh: ssh -i ./id_rsa ... I have these lines in ssh debug trace: debug1: Offering public key: ./id_rsa debug3: send_pubkey_test debug2: we sent a ...
7
votes
2answers
5k views

How to revoke an ssh certificate (not ssh identity file!)

I've generated an ssh certificate like this: ssh-keygen -f ca_key # generate a ssh keypair for use as a certificate generate a host key ssh-keygen -s ca_key -I cert_identifier -h host_key.pub ...
7
votes
4answers
3k views

Automatically-reconnecting TCP tunnel

I have an unreliable network connection between two machines: sometimes active TCP connections get dropped for reasons beyond my control. I want to establish a reliable TCP connection between the two ...
6
votes
2answers
18k views

SSH sessions terminate abruptly with message: Corrupted MAC on input. Disconnecting: Packet corrupt

We have a Dell PowerEdge 840 Server running CentOS 6.0 64 bit with 2GB ECC memory. When any user sshs in, after some time the session gets terminated with the output: Corrupted MAC on input. Packet ...
6
votes
3answers
7k views

Trying to setup chroot'd rsync

I'm trying to set up a backup server. I want to chroot each user (client) to its home directory, and only allow it to use sftp and rsync. I quickly discovered that I was not the only one trying to do ...
4
votes
4answers
7k views

How Ubuntu cloud version enforces the “no root login” over ssh?

I'm looking to tweak ubuntu cloud version default setup where is denies root login. Attempting to connect to such machine yields: maxim@maxim-desktop:~/workspace/integration/deployengine$ ssh root@...
4
votes
1answer
2k views

ssh agent forwarding fails with “Could not open a connection to your authentication agent”

I receive a Could not open a connection to your authentication agent error message when I attempt to connect from an intermediate server to a third server using the agent forwarding option (-A) of an ...
3
votes
1answer
2k views

SSH from Windows to Linux with AD certificates

I have a Windows client machine connected to Active Directory and a Linux server also connected to Active Directory (through PAM w/ LDAP), and I want to be able to do password-less SSH from Windows to ...
3
votes
4answers
4k views

Looking for a one step solution to appending my SSH public key to a server's authorized_keys?

To get my public key onto a server I normal copy the contents of my public key, then SSH into the server, then I run vi .ssh/authorized_keys, then paste my key into the file and save. There has got ...