Cisco Ios Generate Rsa Key

  • October 2, 2015
  • Posted by: Syed Shujaat
  • Category: Cisco, Networking Solutions

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. Two keys are generated. Let’s generate a 2048 bit RSA key pair: R1(config)#crypto key generate rsa modulus 2048 The name for the keys will be: R1.NETWORKLESSONS.LOCAL% The. About this document This document is intended to show how one can get big outputs for IOS CLI using SSH public key authentication. It might be useful when you have scripts executed automatically to obtain information for monitoring purposes. Initial configration In this example I'm using an. Cisco IOS Security Command Reference: Commands A to C, Cisco IOS XE Release 3SE (Catalyst 3850 Switches) 3 crypto key generate rsa. Crypto key generate rsa. Cisco IOS Security Command Reference: Commands A to C, Cisco IOS XE Release 3SE (Catalyst 3850 Switches) 8 crypto key generate rsa crypto key generate rsa.

Sep 18, 2018  In this lesson, we will learn how to configure SSH on Cisco IOS enabled devices. This tutorial will show you how to enable SSH, generating RSA key, and then allowing on SSH remote management protocol under the VTY interfaces. Dec 26, 2013  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.

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

Cisco Ios Generate Rsa Keys

2. router (Config)# ip domain-name example.com

router (Config)# crypto key generate rsa

Cisco Ios Generate Rsa Key

how many bits in the modulus [512] :1024

router (Config)# ip ssh version2

router (Config)# CTRL Z

Cisco Ios Generate Rsa Key

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.

Router360 bits512 bits1024 bits2048 bits (maximum)
Cisco 250011 seconds20 seconds4 minutes, 38 secondsMore than 1 hour
Cisco 4700Less than 1 second1 second4 seconds50 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.
Note Effective with Cisco IOS XE Release 2.4 and Cisco IOS Release 15.1(1)T, the maximum key size was expanded to 4096 bits for private key operations. The maximum for private key operations prior to these releases was 2048 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.
CommandDescription
copyCopies any file from a source to a destination, use the copy command in privileged EXEC mode.
cryptokeystorageSets the default storage location for RSA key pairs.
debugcryptoengineDisplays debug messages about crypto engines.
hostnameSpecifies or modifies the hostname for the network server.
ipdomain-nameDefines a default domain name to complete unqualified hostnames (names without a dotted-decimal domain name).
showcryptokeymypubkeyrsaDisplays the RSA public keys of your router.
show crypto pki certificatesDisplays information about your PKI certificate, certification authority, and any registration authority certificates.

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish.

Privacy Overview

This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may have an effect on your browsing experience.

Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.

Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.