Generate Rsa Key On Cisco Switch
- How To Generate Rsa Key In Cisco Switch
- Generate Rsa Key On Cisco Switch Windows 10
- Cisco Generate Crypto Key
- Generate Rsa Key On Cisco Switch Windows 10
- Generate Rsa Key On Cisco Switch Download
Jun 28, 2007 ip domain-name rtp.cisco.com!- Generate an SSH key to be used with SSH. Crypto key generate rsa ip ssh time-out 60 ip ssh authentication-retries 2. 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. SSH Public Key Authentication on Cisco IOS. We have to configure our Cisco IOS router (or switch) first. Let’s generate a 2048 bit RSA key pair: R1. Dec 24, 2019 I then ran the crypto key generate rsa command to generate another key pair and still got the same end date. I then checked the version of my other switches in the network to see why they were not alerting about certificate end date and they were using iOS15.2.6 or later while this switch is still on 15.2.2. Actually, for maximum security, you can enable a username/password and public key authentication for access to your switch. In this article, I’ll show you how to enable public key authentication on an SG300 Cisco switch and how to generate the public and private key pairs using puTTYGen. I’ll then show you how to login using the new keys.
- October 2, 2015
- Posted by: Syed Shujaat
- Category: Cisco, Networking Solutions
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.
NOTE: Before issuing this command, ensure that your router has a hostname and IP domain name configured (with the hostname and ipdomain-name commands).
You will be unable to complete the cryptokeygeneratersacommand without a hostname and IP domain name. (This situation is not true when you generate only a named key pair.)
Here are the steps to Enable SSH and Crypto Key setup : 2 config must requried for SSH
1 Setup Local VTY line User ID and password
router (Config) # Line VTY 0 15
router (Config-line)# login local
router (Config-line)# Exit
!!! create local login ID/Pass
router (Config)# username [loginid] password [cisco]
router (Config)# username loginid1 password cisco1
2. router (Config)# ip domain-name example.com
router (Config)# crypto key generate rsa
how many bits in the modulus [512] :1024
router (Config)# ip ssh version2
router (Config)# CTRL Z
Note | Secure Shell (SSH) may generate an additional RSA key pair if you generate a key pair on a router having no RSA keys. The additional key pair is used only by SSH and will have a name such as {router_FQDN }.server. For example, if a router name is “router1.cisco.com,” the key name is “router1.cisco.com.server.” |
This command is not saved in the router configuration; however, the RSA keys generated by this command are saved in the private configuration in NVRAM (which is never displayed to the user or backed up to another device) the next time the configuration is written to NVRAM.
Modulus Length
When you generate RSA keys, you will be prompted to enter a modulus length. The longer the modulus, the stronger the security. However, a longer modules take longer to generate (see the table below for sample times) and takes longer to use.
The size of Key Modulus range from 360 to 2048. Choosing modulus greater than 512 will take longer time.
| Router | 360 bits | 512 bits | 1024 bits | 2048 bits (maximum) |
|---|---|---|---|---|
| Cisco 2500 | 11 seconds | 20 seconds | 4 minutes, 38 seconds | More than 1 hour |
| Cisco 4700 | Less than 1 second | 1 second | 4 seconds | 50 seconds |
Cisco IOS software does not support a modulus greater than 4096 bits. A length of less than 512 bits is normally not recommended. In certain situations, the shorter modulus may not function properly with IKE, so we recommend using a minimum modulus of 2048 bits.
Syntax Description : Optional Strings to embed with SSH Crypto key
| general-keys | (Optional) Specifies that a general-purpose key pair will be generated, which is the default. | ||
| usage-keys | (Optional) Specifies that two RSA special-usage key pairs, one encryption pair and one signature pair, will be generated. | ||
| signature | (Optional) Specifies that the RSA public key generated will be a signature special usage key. | ||
| encryption | (Optional) Specifies that the RSA public key generated will be an encryption special usage key. | ||
| labelkey-label | (Optional) Specifies the name that is used for an RSA key pair when they are being exported.If a key label is not specified, the fully qualified domain name (FQDN) of the router is used. | ||
| exportable | (Optional) Specifies that the RSA key pair can be exported to another Cisco device, such as a router. | ||
| modulusmodulus-size | (Optional) Specifies the IP size of the key modulus.By default, the modulus of a certification authority (CA) key is 1024 bits. The recommended modulus for a CA key is 2048 bits. The range of a CA key modulus is from 350 to 4096 bits.
| ||
| storagedevicename: | (Optional) Specifies the key storage location. The name of the storage device is followed by a colon (:). | ||
| redundancy | (Optional) Specifies that the key should be synchronized to the standby CA. | ||
| ondevicename: | (Optional) Specifies that the RSA key pair will be created on the specified device, including a Universal Serial Bus (USB) token, local disk, or NVRAM. The name of the device is followed by a colon (:).Keys created on a USB token must be 2048 bits or less. |
| Command | Description |
|---|---|
| copy | Copies any file from a source to a destination, use the copy command in privileged EXEC mode. |
| cryptokeystorage | Sets the default storage location for RSA key pairs. |
| debugcryptoengine | Displays debug messages about crypto engines. |
| hostname | Specifies or modifies the hostname for the network server. |
| ipdomain-name | Defines a default domain name to complete unqualified hostnames (names without a dotted-decimal domain name). |
| showcryptokeymypubkeyrsa | Displays the RSA public keys of your router. |
| show crypto pki certificates | Displays information about your PKI certificate, certification authority, and any registration authority certificates. |
Contents
Introduction
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.
| CatOS SSH | |
|---|---|
| Device | SSH Support |
| Cat 4000/4500/2948G/2980G (CatOS) | K9 images as of 6.1 |
| Cat 5000/5500 (CatOS) | K9 images as of 6.1 |
| Cat 6000/6500 (CatOS) | K9 images as of 6.1 |
| IOS SSH | |
| Device | SSH Support |
| Cat 2950* | 12.1(12c)EA1 and later |
| Cat 3550* | 12.1(11)EA1 and later |
| Cat 4000/4500 (Integrated Cisco IOS Software)* | 12.1(13)EW and later ** |
| Cat 6000/5500 (Integrated Cisco IOS Software)* | 12.1(11b)E and later |
| Cat 8540/8510 | 12.1(12c)EY and later, 12.1(14)E1 and later |
| No SSH | |
| Device | SSH Support |
| Cat 1900 | no |
| Cat 2800 | no |
| Cat 2948G-L3 | no |
| Cat 2900XL | no |
| Cat 3500XL | no |
| Cat 4840G-L3 | no |
| Cat 4908G-L3 | no |
How To Generate Rsa Key In Cisco Switch
* 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. /generate-cert-pem-key-pem.html.
Network Diagram
Switch Configuration
Disabling SSH
In some situations it may be neccessary to disable SSH on the switch. 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
Generate Rsa Key On Cisco Switch Windows 10
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:
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).
Cisco Generate Crypto Key
The workarounds for this problem are:
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.
Generate Rsa Key On Cisco Switch Windows 10
A bug has been filed about this issue. For more information, refer to Cisco bug ID CSCtc41114 (registered customers only) .