Generate Rsa Keys Cisco Switch

1. Generate Rsa Keys Cisco Switch 2017
2. Cisco Generate Crypto Key

Contents

Introduction

Jun 11, 2019 SW1 ( config)# crypto key generate rsa. How many bits in the modulus 512: 1024% Generating 1024 bit RSA keys, keys will be non-exportableOK Set the size of key to 1024 bits. If your Cisco Switch is running an older version of Cisco IOS image, then it is extremely recommended that you upgrade to latest Cisco IOS. Aug 25, 2016  crypto key generate rsa Example: Switch (config)# crypto key generate rsa Enables the SSH server for local and remote authentication on the Switch and generates an RSA key pair. Generating an RSA key pair for the Switch automatically enables SSH. So it looks as if there is no point in the 'crypto key generate rsa' command if i follow it up with the 'crypto key generate rsa usage-keys label sshkeys mod 1024' command, i just wanted to make sure the first wasn't need for the second to work or something screwy like that.

This document gives step-by-step instructions to configure Secure Shell (SSH) Version 1 on Catalyst switches running Catalyst OS (CatOS). The version tested is cat6000-supk9.6-1-1c.bin.

Prerequisites

Requirements

This table shows the status of SSH support in the switches. Registered users can access these software images by visiting the Software Center.

* Configuration is covered in Configuring Secure Shell on Routers and Switches Running Cisco IOS.

** There is no support for SSH in 12.1E train for Catalyst 4000 running Integrated Cisco IOS Software.

Refer to Encryption Software Export Distribution Authorization Form in order to apply for 3DES.

This document assumes that authentication works prior to implementation of SSH (through the Telnet password, TACACS+) or RADIUS. SSH with Kerberos is not supported prior to the implementation of SSH.

Components Used

This document addresses only the Catalyst 2948G, Catalyst 2980G, Catalyst 4000/4500 series, Catalyst 5000/5500 series, and Catalyst 6000/6500 series running the CatOS K9 image. For more details, refer to the Requirements section of this document.

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 working in a live network, ensure that you understand the potential impact of any command before using it.

Conventions

For more information on document conventions, see the Cisco Technical Tips Conventions.

Network Diagram

Switch Configuration

Disabling SSH

In some situations it may be neccessary to disable SSH on the switch. Generate csr private key windows. You must verify whether SSH is configured on the switch and if so, disable it.

To verify if SSH has been configured on the switch, issue the show crypto key command. If the output displays the RSA key, then SSH has been configured and enabled on the switch. An example is shown here.

To remove the crypto key, issue the clear crypto key rsa command to disable SSH on the switch. An example is shown here.

debug in the Catalyst

To turn on debugs, issue the set trace ssh 4 command.

To turn off debugs, issue the set trace ssh 0 command.

debug Command Examples of a Good Connection

Solaris to Catalyst, Triple Data Encryption Standard (3DES), Telnet Password

Solaris

Catalyst

PC to Catalyst, 3DES, Telnet Password

Catalyst

Solaris to Catalyst, 3DES, Authentication, Authorization, and Accounting (AAA) Authentication

Solaris

Catalyst

debug Command Examples of What Can Go Wrong

Catalyst debug with Client Attempting [unsupported] Blowfish Cipher

Catalyst debug with Bad Telnet Password

Catalyst debug with Bad AAA Authentication

Troubleshoot

This section deals with different troubleshooting scenarios related to SSH configuration on Cisco switches.

Cannot Connect to Switch through SSH

Problem:

Generate Rsa Keys Cisco Switch 2017

Cannot connect to the switch using SSH.

The debug ip ssh command shows this output:

Solution:

This problem occurs because of either of these reasons:

• New SSH connections fail after changing the hostname.

• SSH configured with non-labeled keys (having the router FQDN).

The workarounds for this problem are:

Cisco Generate Crypto Key

• If the hostname was changed and SSH is no longer working, then zeroize the new key and create another new key with the proper label.

• Do not use anonymous RSA keys (named after the FQDN of the switch). Use labeled keys instead.

In order to resolve this problem forever, upgrade the IOS software to any of the versions in which this problem is fixed.

A bug has been filed about this issue. For more information, refer to Cisco bug ID CSCtc41114 (registered customers only) .

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