Where is ssh config ubuntu

It will connect to the SSH server using the default port, The parameters of the third host are defined for all hosts. The IdentifyFile parameter has defined the location of the public key. The compression parameter has been defined to compress the data. Here, the -i option has been used with the ssh command to mention the path of the public key.

Here, the -i option has been used with the ssh command to mention the path of the public key, and the -p option has been used to define the port number. Using the custom SSH config file for making an SSH connection with the server has been shown in this tutorial by using the local host of the two accounts. You can follow the same process to make an SSH connection with the host of the remote network. I am a trainer of web programming courses.

I like to write article or tutorial on various IT topics. When the user needs to access the remote servers frequently using SSH protocol, then the user will require to remember the IP addresses, usernames, different port numbers, and command-line options. But it is not an efficient way to do the tasks.

This problem can be solved in multiple ways. Once you've made your changes see the suggestions in the rest of this page , you can apply them by saving the file then doing: sudo restart ssh If you get the error, "Unable to connect to Upstart", restart ssh with the following: sudo systemctl restart ssh Configuring OpenSSH means striking a balance between security and ease-of-use.

Ubuntu's default configuration tries to be as secure as possible without making it impossible to use in common use cases.

This page discusses some changes you can make, and how they affect the balance between security and ease-of-use. When reading each section, you should decide what balance is right for your specific situation. Disable Password Authentication Because a lot of people with SSH servers use weak passwords, many online attackers will look for an SSH server, then start guessing passwords at random.

An attacker can try thousands of passwords in an hour, and guess even the strongest password given enough time. The recommended solution is to use SSH keys instead of passwords. To be as hard to guess as a normal SSH key, a password would have to contain random letters and numbers. If you'll always be able to log in to your computer with an SSH key, you should disable password authentication altogether. If you disable password authentication, it will only be possible to connect from computers you have specifically approved.

This massively improves your security, but makes it impossible for you to connect to your own computer from a friend's PC without pre-approving the PC, or from your own laptop when you accidentally delete your key.

It's recommended to disable password authentication unless you have a specific reason not to. For example, you could connect over the Internet to your PC, tunnel a remote desktop connection, and access your desktop. This is known as "port forwarding". By default, you can also tunnel specific graphical applications through an SSH session.

This is known as "X11 forwarding". This means you have installed and enabled SSH on your remote machine, which can now accept commands from your SSH client. Once you have gone through the process of enabling SSH on Ubuntu If you do not know the IP address, you can quickly identify it through the terminal by typing the command:. Once you have identified and typed in all the information, you have officially logged into your server. You are free to manage it from the comfort of your workstation safely.

Gedit is a text editor which comes by default in Ubuntu, but you can also use other text editors such as nano. If you prefer using nano, you can easily install it by running the following command:. When prompted, type in your password and press y yes to permit the installation. Now that you have opened the file using any of the text editors recommended above find and make any necessary changes. For example, if you wish to change the port number to listen on TCP port instead of the default TCP port 22, find the line in which Port 22 is specified by default, and change it to Port Note that CheckHostIP is not available for connects with a proxy command.

This directive is useful in conjunction with nc 1 and its proxy support. For example, the following directive would connect via an HTTP proxy at PubkeyAuthentication Specifies whether to try public key authentication. This option applies to protocol version 2 only. RekeyLimit Specifies the maximum amount of data that may be transmitted before the session key is renegotiated, optionally followed a maximum amount of time that may pass before the session key is renegotiated.

RemoteForward Specifies that a TCP port on the remote machine be forwarded over the secure channel to the specified host and port from the local machine. Privileged ports can be forwarded only when logging in as root on the remote machine. RequestTTY Specifies whether to request a pseudo-tty for the session. This option mirrors the -t and -T flags for ssh 1. This option applies to protocol version 1 only and requires ssh 1 to be setuid root. RSA authentication will only be attempted if the identity file exists, or an authentication agent is running.

SendEnv Specifies what variables from the local environ 7 should be sent to the server. Note that environment passing is only supported for protocol 2. The server must also support it, and the server must be configured to accept these environment variables. Variables are specified by name, which may contain wildcard characters. Multiple environment variables may be separated by whitespace or spread across multiple SendEnv directives.

The default is not to send any environment variables. ServerAliveCountMax Sets the number of server alive messages see below which may be sent without ssh 1 receiving any messages back from the server.

If this threshold is reached while server alive messages are being sent, ssh will disconnect from the server, terminating the session. It is important to note that the use of server alive messages is very different from TCPKeepAlive below.

The server alive messages are sent through the encrypted channel and therefore will not be spoofable. The server alive mechanism is valuable when the client or server depend on knowing when a connection has become inactive. The default value is 3. If, for example, ServerAliveInterval see below is set to 15 and ServerAliveCountMax is left at the default, if the server becomes unresponsive, ssh will disconnect after approximately 45 seconds.

This option applies to protocol version 2 only; in protocol version 1 there is no mechanism to request a response from the server to the server alive messages, so disconnection is the responsibility of the TCP stack. ServerAliveInterval Sets a timeout interval in seconds after which if no data has been received from the server, ssh 1 will send a message through the encrypted channel to request a response from the server. The default is 0, indicating that these messages will not be sent to the server, or if the BatchMode option is set.

This option forces the user to manually add all new hosts. The host keys of known hosts will be verified automatically in all cases.

If they are sent, death of the connection or crash of one of the machines will be properly noticed. This option only uses TCP keepalives as opposed to using ssh level keepalives , so takes a long time to notice when the connection dies. As such, you probably want the ServerAliveInterval option as well. However, this means that connections will die if the route is down temporarily, and some people find it annoying. This is important in scripts, and many users want it too.

Tunnel Request tun 4 device forwarding between the client and the server. UsePrivilegedPort Specifies whether to use a privileged port for outgoing connections. User Specifies the user to log in as. This can be useful when a different user name is used on different machines. This saves the trouble of having to remember to give the user name on the command line. UserKnownHostsFile Specifies one or more files to use for the user host key database, separated by whitespace.

XAuthLocation Specifies the full pathname of the xauth 1 program. A pattern-list is a comma-separated list of patterns. The format of this file is described above. This file is used by the SSH client. It may be group-writable provided that the group in question contains only the user.