2/4/2021 Generate Rsa Key Cisco Switch
Sep 20, 2010 This tutorial demonstrates how to quickly and easily enable SSH on a new Cisco router or switch. This will enable secure terminal sessions to the device without the risks associated with plain. As of Cisco IOS Release 12.4(11)T, peer public RSA key modulus values up to 4096 bits are automatically supported. The largest private RSA key modulus is 4096 bits. Therefore, the largest RSA private key a router may generate or import is 4096 bits. SSH Public Key Authentication on Cisco IOS. PKI (Public Key Authentication) is an authentication method that uses a key pair for authentication instead of a password. Putty itself can’t generate any RSA keys but we can do this with. Before we can test this, we have to configure our Cisco IOS router (or switch. May 20, 2014 Author, teacher, and talk show host Robert McMillen shows you how to use the Cisco ASA version 9 generate RSA keys command.
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Feb 21, 2015 How to set up Secure Shell (SSH) in Cisco Packet Tracer What is Secure Shell (SSH) you might ask!? SSH protocol uses public-key cryptography to.
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ContentsIntroduction
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.
PrerequisitesRequirements
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:
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 DiagramTest AuthenticationAuthentication 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 SettingsPrevent 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:
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. Generate google api key for website. 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:
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.
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.
Generate Rsa Key Cisco Switch Replacement
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:
You can use this command from Solaris:
Restrict SSH access to a subnetHow To Generate Rsa Key Cisco Switch
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:
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:
https://pianotree730.weebly.com/blog/generate-public-private-key-pair-python. Configure SSH v2:
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.
Sample Debug OutputRouter 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 DebugRouter DebugBad PasswordRouter DebugSSH Client Sends Unsupported (Blowfish) CipherRouter DebugGeting 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.
Cisco bug ID CSCsa83601 (registered customers only) has been filed to address this behaviour.
Troubleshooting Tips
Related InformationComments are closed.
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