SSH (Secure SHell) is a protocol for running commands on a remote computer.

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16
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7answers
33k views

How to download a file through an SSH server?

I have a server in USA (Linux box B), and my home PC (Linux box A), and I need download a file from website C, The issue is, it is very slow to download a file direct from A, so I need download the ...
11
votes
4answers
59k views

Keeping a process running after putty or terminal has been closed [duplicate]

I'm running a node.js server off of a raspbian (Debian) machine, and I'd like to start and stop the server remotely. This for me means using putty to access the shell, except when I close out of the ...
12
votes
2answers
37k views

SSH key-based authentication: known_hosts vs authorized_keys

I read about setting up ssh keys in Linux and have some questions. Correct me if I'm wrong… Let's say host tr-lgto wants to connect to host tr-mdm using ssh. If we want to be sure that it's the real ...
50
votes
2answers
7k views

How does SSH connection survive a network restart?

From a Linux SSH shell, type /etc/init.d/network restart to restart the network service. I expect my SSH connection to die since the network service goes down. But it doesn't. Very cool. But how does ...
18
votes
3answers
2k views

How to prevent shutdown when an SSH user is logged in?

I'm administrating a networked environment and I had an interesting situation arise yesterday. When a host is required to shutdown by a regular user, it refuses to do so if other users are logged in ...
16
votes
9answers
76k views

ssh_exchange_identification: read: Connection reset by peer

I am on OS X trying to ssh into a ubuntu 12.04 server. I was able to SSH in -- until abruptly stuff stopped working. I've read online to use the -v to debug this. Output is shown below. If I ssh into ...
11
votes
2answers
989 views

Understanding SSH tunnels

I have linux (Ubuntu) server which I have root access to through ssh (port 22) only. On that server there is a MySQL database listening on port 3306. Is it possible to use putty (on my machine) and ...
7
votes
5answers
3k views

How to effectively use screen and SSH?

I'd like to configure SSH and screen such that a login will always reattach to a screen session. Ideally, that session would not quit but detach when I press C-d. How can this be achieved? And what ...
23
votes
4answers
17k views

Why SSH takes a long time to Connect

I have noticed that some Linux Servers in Network takes long time to connect using ssh. Situations: There are two situations I have faced: On some servers some times it takes a long time to ask ...
11
votes
3answers
2k views

How to open a port early in boot process to unlock LUKS via SSH

I have a fully encrypted server running Debian 7 and have set up dropbear and busybox to unlock the LUKS container via SSH (as described in this tutorial and in this U&L answer). Unfortunately, ...
5
votes
2answers
2k views

VPN like solution for SSH Tunneling?

Socksify like program for Fedora? Socksify, tsocks, proxycommand in ssh, they're great softwares/solutions that can be used to "constrain" given apps to use a SOCKS5 proxy (what was created with an ...
39
votes
4answers
33k views

What is the point of sshd “UseDNS” option?

I know what it does, but i don't know why. What attack(s) does it prevent ? Is it relevant for all kind of authentication methods ? (hostbased, password, publickey, keyboard-interactive ...)
12
votes
1answer
3k views

Reusing ssh session for repeated rsync commands [duplicate]

Possible Duplicate: Using an already established SSH channel I have a remote server accessible via a chain of SSH proxies. The resulting channel is wide and fast enough, but setting it up ...
6
votes
2answers
3k views

How can I make ssh ignore .ssh/config?

I have the following in my ~/.ssh/config. HOST 10.2.192.* USER foo PreferredAuthentications publickey IdentityFile ~/.ssh/foo/id_rsa The above configuration lets me connect ...
5
votes
2answers
3k views

Tunnel yum traffic through another server via ssh

I am running a Fedora desktop behind a corporate proxy that is blocking yum traffic (specifically *.gz and *.bz2). I have access to a separate RedHat machine via ssh which can download anything it ...
5
votes
2answers
13k views

Sending function keys (F1-F12) over SSH

I have a Fedora machine that I can SSH to. One of the programs I'd like to use occasionally uses the function keys. The problem is that I'm SSH'ing from an Android tablet (ASUS Transformer Infinity) ...
11
votes
1answer
535 views

How to execute an arbitrary simple command over ssh without knowing the login shell of the remote user?

ssh has an annoying feature in that when you run: ssh user@host cmd and "here's" "one arg" Instead of running that cmd with its arguments on host, it concatenates that cmd and arguments with spaces ...
11
votes
5answers
3k views

How to copy a file that is still being written over ssh?

Here is the situation: I am uploading a large file from client A to a server using sftp. I also need to download this file from the server to client B over ssh. What I would like to do is start ...
6
votes
3answers
19k views

How to write a bash script, that logs onto an other machine to do stuff?

Is it possible to write a bash script, that would be started from machine A, logs in on a different machine B by ssh (both machines A and B would be Linux-Machines), copys some files on to machine B ...
5
votes
7answers
461 views

Are there additional ways to protect SSH connections besides firewall and RSA Keys?

Sometimes I don't have a static IP and need to administrate my web server remotely. I'm looking for any additional layers of protection I could add to make opening port 22 safer. Currently I have ...
5
votes
2answers
6k views

How do I disable remote root login via ssh?

How do I disable remote root login via ssh? I want to log into my server (I use keys on my main comp) then su into root instead of access root directly. I am using Debian. I follow guides online ...
5
votes
2answers
957 views

How can I forward traffic from my publicly available server to a computer that is not publicly available?

My home computer is behind an ISP-level NAT which does not allow me to host game servers as a result. I have a VPS which I use as a web server. I want to host a game server of Minecraft, but the VPS ...
4
votes
3answers
18k views

How to copy between two remote hosts using tar piped into SSH from remote server when behind a firewall?

I'd like to transfer a directory between two servers, but compress the directory on the remote host before transfer, and then uncompress to another host. I'm sure it's possible to pipe everything all ...
3
votes
3answers
940 views

Run a parallel command while waiting for ssh

I need to ssh into a server and check for a service to see if it is up and running. What i do is to use ssh and run a command which calls that service and check the output of that command. I want to ...
1
vote
2answers
11k views

Colorful ssh banner

I would like to colorize my ssh banner. I know I can perform it like so: In /etc/profile I can put: echo -e "\e[1;31m Colorful text" echo -e "\e[0m Reset" But I have some ASCII art in the banner ...
0
votes
3answers
21k views

Method to check connectivity to other server

I want to check connectivity between 2 servers (i.e. if ssh will succeed). The main idea is to check the shortest way between server-a and server-b using a list of middle servers (for example if I'm ...
15
votes
6answers
3k views

OS X: how to keep the computer from sleeping during a ssh session

When I ssh into a OS X computer on my network the session lasts until the OS X goes into sleep mode. Is there a way to prevent this from happening during my SSH session, apart from physically bumping ...
14
votes
2answers
21k views

Use ssh with a specific network interface

I'm using openconnect to connect to vpn. After entering my credentials, I get this: POST https://domain.name/... Got CONNECT response: HTTP/1.1 200 OK CSTP connected. DPD 30, Keepalive 30 Connected ...
12
votes
3answers
14k views

SCP from one server to another without password prompt

What is the best way of doing SCP from one box to the other without prompting for password? There are two servers: Server A (10.152.2.10): /home/oracle/export/files.txt Server B (10.152.2.11): ...
11
votes
2answers
10k views

Starting firefox on a remote host (over ssh) opens a new window locally: what is happening?

I have never noticed this behaviour before, and am a little confused as to what is happening. I have a local copy of firefox running, then ssh (ssh -X <url>) into a remote server and start a ...
9
votes
5answers
25k views

ssh Connection refused: how to troubleshoot?

I'm trying: $ ssh eric@myserver where myserver is a machine in the intranet. I can ping myserver or respond to HTTP on port 8080, etc, but when I try ssh, I get ssh: connect to host myserver port ...
8
votes
2answers
8k views

Not able to ssh in to remote machine using shell script in Crontab

Below is the script which i am trying to run, which runs without any issue for i in `seq 200 2100` do usr=(`ssh -t -t -o ConnectTimeout=60 machine$1 finger | tail -1 | awk '{print$1}'`) echo ...
7
votes
5answers
3k views

Securely tunnel port through intermediate host

I'm looking to route a port for VNC back to my house here. I have to jump over a single host to then hop to my actual work machine. sittinghere will be my local home machine hopper will by the ...
7
votes
3answers
3k views

Bash: interactive remote prompt

I have a script which connects to a remote server and check if some package is installed: ssh root@server 'bash -s' < myscript.sh myscript.sh: OUT=`rpm -qa | grep ntpdate` if [ "$OUT" != "" ] ; ...
6
votes
5answers
9k views

How to securely allow scp, but not ssh

I work from a Mac Book Pro (called foo). I have a server where my customers scp large files to. (called bar). I frequently ssh into bar, and scp a file (called buzz) to my Mac. bob@foo$ ssh bar ...
6
votes
4answers
5k views

What slows down my ssh login?

Everytime I ssh login to a server, it is always very slow. As a reply to my earlier post said, "grepping through a 200 line file should take millisecond or so, so I would doubt its that." I tried ssh ...
5
votes
1answer
17k views

how to connect ssh 'with' specified port?

I know how to connect 'to' a certain port when ssh'ing. ssh user@remotehostip -p XXX but is there a way to establish a ssh 'with' a certain port? I mean, is there a way to specify the port which ...
5
votes
2answers
2k views

Restrict password-less backup with SFTP

I need to perform backup of a server to my computer using Duplicity: duplicity /etc sftp://backup@my.dynamic.ip.address//home/backup Before this can be done, I need to allow password-less access by ...
5
votes
2answers
2k views

Can't share an ssh connection with rsync

In my .ssh/config file I have the following: Host xxx User yyy HostName zzzz ControlMaster auto ControlPath ~/.ssh/%r@%h:%p This works great for multiplexing my ssh connections (i.e. login once, ...
4
votes
2answers
316 views

SSH - How to make X applications run on client?

I have the reverse problem that most people seem to be having. If I start an X application while logged into ssh, it displays on the server(host) machine instead of the client(local). This is the ...
4
votes
3answers
857 views

DynDNS alternative for SSH?

I have an server that has a dynamic IP address and is accessible over SSH. On the server, a script uploads a text file containing the server's public IP address to a web location whenever that address ...
3
votes
1answer
749 views

Disable ForwardX11Timeout without ForwardX11Trusted in OpenSSH Client?

By default, recent versions of OpenSSH automatically set ForwardX11Timeout to 20 minutes if you set ForwardX11Trusted to no. This means that 20 minutes after you start your ssh connection, you can't ...
3
votes
1answer
417 views

Clipboard over SSH session through VIM

I have a server running SSH, when I edit a file with vim on the remote server, :y+ doesn't work since the VIM binary on that linux system wasn't compiled with X support. (E488: Trailing characters) ...
3
votes
2answers
968 views

Fastest ssh X tunneling on a local secure network

I have read in a few websites e.g. (1) that the default ssh cipher is not necessarily the fastest. I work on a local fully secure network. Assuming that security is not an issue and that I just care ...
3
votes
1answer
2k views

Start network service at boot time on CentOS

I've recently reinstalled CentOS onto a computer of mine. I have OpenSSH Server on it now, as did I before I reinstalled the operating system. Here's the difference: Before, SSH started without even ...
3
votes
2answers
6k views

SSH + Sudo + Expect in Bash script: Run command with sudo in remote machine

I am trying to automate the deploy of some .deb packages with an script. I want to execute sudo dpkg -i $myDeb.deb in a list of remote machines I can access with ssh. I've tried to automate the ...
2
votes
1answer
86 views

Jumping ssh hosts without netcat

I have access to an intermediate server to which I can connect with ssh. From there I can connect to other servers: A→B→C, where A is my laptop, B is an intermediate server accepting connections from ...
13
votes
3answers
15k views

Permit root to login via ssh only with key-based authentication

I have some doubts about certain ssh server configurations on /etc/ssh/sshd_config. I want the next behavior: Public key authentication is the only way to authenticate as root (no password ...
9
votes
4answers
1k views

Stopping output from a program run in SSH session NOW

Problem I execute command that outputs LOTS of information through SSH. For example, I foolishly add debug information inside a loop that executes million times, or just run cat /dev/urandom for ...
9
votes
1answer
1k views

Why does SSH not consult /etc/hosts?

I'm administrating a networked environment where the users authenticate over NIS. All machines can be used to SSH into the server but one. On the machine in question, I get the message ssh: connect ...