So, in short: if your router has RSA keys generated, but won't enable SSHv2, enable SSH with the name of the RSA keys, like so: ip ssh rsa keypair-name and then. No ip ssh version 1 Thankfully, this was a lab setup so no SSHv1 traffic was publicly sent, and no actual passwords were used, so mitigation from using a bad SSH version was. Aug 31, 2016  When I try to generate RSA keys for SSH access on a router using the crypto key generate rsa command in config mode, I receive this error:% Invalid input detected at '^' marker. It does not let the router generate the RSA keys to enable SSH access for the router.

1. Please Generate Rsa Keys To Enable Ssh Firefox
2. Generate Rsa Ssh Key
3. Cisco Switch Generate Ssh Keys
4. Please Create Rsa Keys To Enable Ssh
5. Please Generate Rsa Keys To Enable Ssh File
6. Please Generate Rsa Keys To Enable Ssh Download
7. Please Generate Rsa Keys To Enable Ssh On Windows 10

Introduction

This document describes how to generate a private secure shell (SSH) key and use that for username and authentication when logging into the command line interface (CLI) on the Cisco Email Security Appliance (ESA).

1. Oct 02, 2015  SSH Config and crypto key generate RSA command. Use this command to generate RSA key pairs for your Cisco device (such as a router). Keys are generated in pairs–one public RSA key and one private RSA key. If your router already has RSA keys when you issue this command, you will be warned and prompted to replace the existing keys with new keys.
2. Use the key pair. You can use the RSA key pair in the following ways. Specify your SSH key when creating a new cloud server. When you create a cloud server, you can assign a public key from the list of keys. If your key is not already in the list, you may add it, and then assign it. Add a new public key to the list. Under Advanced Options on the Create Server page, click Manage SSH Keys. Select public key for the.
3. Jul 30, 2015 SSH can use either 'RSA' (Rivest-Shamir-Adleman) or 'DSA' ('Digital Signature Algorithm') keys. Both of these were considered state-of-the-art algorithms when SSH was invented, but DSA has come to be seen as less secure in recent years. RSA is the only recommended choice for new keys, so this guide uses 'RSA key' and 'SSH key' interchangeably.
4. Aug 22, 2013 How to Enable SSH on Cisco Switch, Router and ASA. Generate the RSA Keys. The switch or router should have RSA keys that it will use during the SSH process.
5. Oct 20, 2014  How To Create SSH Keys. The first step to configure SSH key authentication to your server is to generate an SSH key pair on your local computer. To do this, we can use a special utility called ssh-keygen, which is included with the standard OpenSSH suite of tools. By default, this will create a 2048 bit RSA key pair, which is fine for most uses.

How to configure SSH Public Key Authentication for login to the ESA without a password

Public-key authentication (PKI) is an authentication method that relies on a generated public/private keypair. With PKI, a special 'key' is generated which has a very useful property: Anyone who can read the public half of the key is able encrypt data which can then only be read by a person who has access to the private half of the key. In this way, having access to the public half of a key allows you to send secret information to anyone with the private half, and to also verify that a person does in fact have access to the private half. It's easy to see how this technique could be used to authenticate.

As a user, you can generate a keypair and then place the public half of the key on a remote system, such as your ESA. That remote system is then able to authenticate your user ID, and allow you to login just by having you demonstrate that you have access to the private half of the keypair. This is done at the protocol level inside SSH and happens automatically.

It does, however, mean that you need to protect the privacy of the private key. On a shared system where you do not have root this can be accomplished by encrypting the private key with a passphrase, which functions similarly to a password. Before SSH can read your private key in order to perform the public key authentication you'll be asked to supply the passphrase so that the private key can be decrypted. On more secure systems (like a machine where you are the only user, or a machine at your home where no strangers will have physical access) you can simplify this process either by creating an unencrypted private key (with no passphrase) or by entering your passphrase once and then caching the key in memory for the duration of your time at the computer. OpenSSH contains a tool called ssh-agent which simplifies this process.

ssh-keygen example for Linux/Unix

Complete the following steps to set up your a linux/unix workstation (or server) to connect to the ESA without a password. In this example, we will not specify as passphrase.

1) On your workstation (or server), generate a private key using the Unix command ssh-keygen:

(*the above was generated from an Ubuntu 14.04.1)

2) Open the public key file (id_rsa.pub) created in #1 and copy the output:

3) Login to your appliance and configure your ESA to recognize your workstation (or server) using the public SSH key that you created in #1, and commitRegistry reviver license key generator download. the changes. Notice the password prompt during login:

4) Exit out of the appliance, and re-login. Notice the password prompt is removed, and access is directly granted:

ssh-keygen example for Windows

Complete the following steps to set up your a Windows workstation (or server) to connect to the ESA without a password. In this example, we will not specify as passphrase.

Note: There are a variation on console application used from Windows. You will need to research and find the solution that works best for your console application. This example will use PuTTy and PuTTyGen.

1) Open PuttyGen.

2) For Type of key to generate, select SSH-2 RSA.

3) Click the Generate button.

4) Move your mouse in the area below the progress bar. When the progress bar is full, PuTTYgen generates your key pair.

5) Type a passphrase in the Key passphrase field. Type the same passphrase in the Confirm passphrase field. You can use a key without a passphrase, but this is not recommended.

6) Click the Save private key button to save the private key.

Note: You must save the private key. You will need it to connect to your machine.

7) Right-click in the text field labeled Public key for pasting into OpenSSH authorized_keys file and choose Select All.

8) Right-click again in the same text field and choose Copy.

9) Using PuTTY, login to your appliance and configure your ESA to recognize your Windows workstation (or server) using the public SSH key that you saved and copied from #6 - #8, and commit the changes. Notice the password prompt during login:

10) From the PuTTy configuration window, and your pre-existing Saved Session for your ESA, choose Connection > SSH > Auth and in the Private key file for authentication field, click Browse and find your saved private key from step #6.

11) Save the Session (profile) in PuTTY, and click Open. Login with the username, if not already saved or specified from the pre-configured Session. Notice the inclusion of 'Authenticating with public key '[FILE NAME OF SAVED PRIVATE KEY]' when logging in:

Related Information

Contents

Introduction

Secure Shell (SSH) is a protocol which provides a secure remote access connection to network devices. Communication between the client and server is encrypted in both SSH version 1 and SSH version 2. Implement SSH version 2 when possible because it uses a more enhanced security encryption algorithm.

This document discusses how to configure and debug SSH on Cisco routers or switches that run a version of Cisco IOS^® Software that supports SSH. This document contains more information on specific versions and software images.

Prerequisites

Requirements

The Cisco IOS image used must be a k9(crypto) image in order to support SSH. For example c3750e-universalk9-tar.122-35.SE5.tar is a k9 (crypto) image.

Components Used

The information in this document is based on Cisco IOS 3600 Software (C3640-IK9S-M), Release 12.2(2)T1.

SSH was introduced into these Cisco IOS platforms and images:

• SSH Version 1.0 (SSH v1) server was introduced in some Cisco IOS platforms and images that start in Cisco IOS Software Release 12.0.5.S.

• SSH client was introduced in some Cisco IOS platforms and images starting in Cisco IOS Software Release 12.1.3.T.

• SSH terminal-line access (also known as reverse-Telnet) was introduced in some Cisco IOS platforms and images starting in Cisco IOS Software Release 12.2.2.T.

• SSH Version 2.0 (SSH v2) support was introduced in some Cisco IOS platforms and images starting in Cisco IOS Software Release 12.1(19)E.

• Refer to How to Configure SSH on Catalyst Switches Running CatOS for more information on SSH support in the switches.

Refer to the Software Advisor (registered customers only) for a complete list of feature sets supported in different Cisco IOS Software releases and on different platforms.

The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If you are in a live network, make sure that you understand the potential impact of any command before you use it.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

SSH v1 vs. SSH v2

Use the Cisco Software Advisor (registered customers only) in order to help you find the version of code with appropriate support for either SSH v1 or SSH v2.

Network Diagram

Test Authentication

Authentication Test without SSH

First test the authentication without SSH to make sure that authentication works with the router Carter before you add SSH. Authentication can be with a local username and password or with an authentication, authorization, and accounting (AAA) server that runs TACACS+ or RADIUS. (Authentication through the line password is not possible with SSH.) This example shows local authentication, which lets you Telnet into the router with username 'cisco' and password 'cisco.'

Authentication Test with SSH

In order to test authentication with SSH, you have to add to the previous statements in order to enable SSH on Carter and test SSH from the PC and UNIX stations.

At this point, the show crypto key mypubkey rsa command must show the generated key. After you add the SSH configuration, test your ability to access the router from the PC and UNIX station. If this does not work, see the debug section of this document.

Optional Configuration Settings

Prevent Non-SSH Connections

If you want to prevent non-SSH connections, add the transport input ssh command under the lines to limit the router to SSH connections only. Straight (non-SSH) Telnets are refused.

Test to make sure that non-SSH users cannot Telnet to the router Carter.

Set Up an IOS Router or Switch as SSH Client

There are four steps required to enable SSH support on a Cisco IOS router:

1. Configure the hostname command.

2. Configure the DNS domain.

3. Generate the SSH key to be used.

4. Enable SSH transport support for the virtual type terminal (vtys).

If you want to have one device act as an SSH client to the other, you can add SSH to a second device called Reed. These devices are then in a client-server arrangement, where Carter acts as the server, and Reed acts as the client. The Cisco IOS SSH client configuration on Reed is the same as required for the SSH server configuration on Carter.

Issue this command to SSH from the Cisco IOS SSH client (Reed) to the Cisco IOS SSH server (Carter) in order to test this:

• SSH v1:

• SSH v2:

Please Generate Rsa Keys To Enable Ssh Firefox

Setup an IOS Router as an SSH server that performs RSA based User Authentication

Complete these steps in order to configure the SSH server to perform RSA based authentication.

1. Specify the Host name.

2. Define a default domain name.

3. Generate RSA key pairs.

4. Configure SSH-RSA keys for user and server authentication.

5. Configure the SSH username.

6. Specify the RSA public key of the remote peer.

7. Specify the SSH key type and version. (optional)

8. Exit the current mode and return to privileged EXEC mode.

   Note: Refer to Secure Shell Version 2 Support for more information.

Add SSH Terminal-Line Access

If you need outbound SSH terminal-line authentication, you can configure and test SSH for outbound reverse Telnets through Carter, which acts as a comm server to Philly.

If Philly is attached to Carter's port 2, then you can configure SSH to Philly through Carter from Reed with the help of this command:

• SSH v1:

• SSH v2:

You can use this command from Solaris:

Restrict SSH access to a subnet

You need to limit SSH connectivity to a specific subnetwork where all other SSH attempts from IPs outside the subnetwork should be dropped.

You can use these steps to accomplish the same:

1. Define an access-list that permits the traffic from that specific subnetwork.

2. Restrict access to the VTY line interface with an access-class.

Generate Rsa Ssh Key

This is an example configuration. In this example only SSH access to the 10.10.10.0 255.255.255.0 subnet is permitted, any other is denied access.

Note: The same procedure to lock down the SSH access is also applicable on switch platforms.

Configure the SSH Version

Configure SSH v1:

Configure SSH v2:

Cisco Switch Generate Ssh Keys

Configure SSH v1 and v2:

Note: You receive this error message when you use SSHv1:

Note: Cisco bug ID CSCsu51740 (registered customers only) is filed for this issue. Workaround is to configure SSHv2.

Variations on banner Command Output

The banner command output varies between the Telnet and different versions of SSH connections. This table illustrates how different banner command options work with various types of connections.

Unable to Display the Login Banner

SSH version 2 supports the login banner. The login banner is displayed if the SSH client sends the username when it initiates the SSH session with the Cisco router. For example, when the Secure Shell ssh client is used, the login banner is displayed. When the PuTTY ssh client is used, the login banner is not displayed. This is because Secure Shell sends the username by default and PuTTY does not send the username by default.

The Secure Shell client needs the username to initiate the connection to the SSH enabled device. The Connect button is not enabled if you do not enter the host name and username. This screenshot shows that the login banner is displayed when Secure Shell connects to the router. Then, the login banner password prompt displays.

The PuTTY client does not require the username to initiate the SSH connection to the router. This screenshot shows that the PuTTY client connects to the router and prompts for the username and password. It does not display the login banner.

This screen shot shows that the login banner is displayed when PuTTY is configured to send the username to the router.

debug and show Commands

Before you issue the debug commands described and illustrated here, refer to Important Information on Debug Commands. Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output.

• debug ip ssh—Displays debug messages for SSH.

• show ssh—Displays the status of SSH server connections.

• show ip ssh—Displays the version and configuration data for SSH.

  • Version 1 Connection and no Version 2

  • Version 2 Connection and no Version 1

  • Version 1 and Version 2 Connections

Sample Debug Output

Router Debug

Note: Some of this good debug output is wrapped to multiple lines because of spatial considerations.

Server Debug

Note: This output was captured on a Solaris machine.

What can go Wrong

These sections have sample debug output from several incorrect configurations.

SSH From an SSH Client Not Compiled with Data Encryption Standard (DES)

Solaris Debug

Please Create Rsa Keys To Enable Ssh

Router Debug

Bad Password

Router Debug

SSH Client Sends Unsupported (Blowfish) Cipher

Router Debug

Geting the '%SSH-3-PRIVATEKEY: Unable to retrieve RSA private key for' Error

If you receive this error message, it may be caused due to any change in the domain name or host name. In order to resolve this, try these workarounds.

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• Zeroize the RSA keys and re-generate the keys.

• If the previous workaround does not work, try these steps:

  1. Zeroize all RSA keys.

  2. Reload the device. /windows-server-2008-standard-product-key-generator.html.

  3. Create new labeled keys for SSH.

Cisco bug ID CSCsa83601 (registered customers only) has been filed to address this behaviour.

Troubleshooting Tips

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• If your SSH configuration commands are rejected as illegal commands, you have not successfully generated a RSA key pair for your router. Make sure you have specified a host name and domain. Then use the crypto key generate rsa command to generate an RSA key pair and enable the SSH server.

• When you configure the RSA key pair, you might encounter these error messages:

  1. No hostname specified

     You must configure a host name for the router using the hostname global configuration command.

  2. No domain specified

     You must configure a host domain for the router using the ip domain-name global configuration command.

• The number of allowable SSH connections is limited to the maximum number of vtys configured for the router. Each SSH connection uses a vty resource.

• SSH uses either local security or the security protocol that is configured through AAA on your router for user authentication. When you configure AAA, you must ensure that the console is not running under AAA by applying a keyword in the global configuration mode to disable AAA on the console.

• No SSH server connections running.

  This output suggests that the SSH server is disabled or not enabled properly. If you have already configured SSH, it is recommended that you reconfigure the SSH server in the device. Complete these steps in order to reconfigure SSH server on the device.

  1. Delete the RSA key pair. After the RSA key pair is deleted, the SSH server is automatically disabled.

     Note: It is important to generate a key-pair with at least 768 as bit size when you enable SSH v2.

     Caution: This command cannot be undone after you save your configuration, and after RSA keys have been deleted, you cannot use certificates or the CA or participate in certificate exchanges with other IP Security (IPSec) peers unless you reconfigure CA interoperability by regenerating RSA keys, getting the CA's certificate, and requesting your own certificate again.Refer to crypto key zeroize rsa - Cisco IOS Security Command Reference, Release 12.3 for more information on this command.

  2. Reconfigure the hostname and domain name of the device.

  3. Generate an RSA key pair for your router, which automatically enables SSH.

     Refer to crypto key generate rsa - Cisco IOS Security Command Reference, Release 12.3 for more information on the usage of this command.

     Note: You can receive the SSH2 0: Unexpected mesg type received error message due to a packet received that is not understandable by the router. Increase the key length while you generate rsa keys for ssh in order to resolve this issue.

  4. Configure SSH server. In order to enable and configure a Cisco router/switch for SSH server, you can configure SSH parameters. If you do not configure SSH parameters, the default values are used.

     ip ssh {[timeout seconds] [authentication-retries integer]}

     Refer to ip ssh - Cisco IOS Security Command Reference, Release 12.3 for more information on the usage of this command.

Please Generate Rsa Keys To Enable Ssh On Windows 10

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