Generate Rsa Key Pair Cisco Asa
Generate Rsa Key Pair Cisco Asa 4,8/5 3961 reviews
  • October 2, 2015
  • Posted by: Syed Shujaat
  • Category: Cisco, Networking Solutions
  1. Generate Rsa Crypto Key Cisco
  2. Rsa Key Pair Cisco
  3. Generate Rsa Key Pair Cisco Asa 2
  4. Generate Rsa Key Pair Cisco Asa 2
  5. Openssl Generate Rsa Key Pair

If you want to generate RSA key pairs, use the crypto key generate rsa command: hostname/contexta(config)# crypto key generate rsa If you do not use additional keywords, this command generates one general purpose RSA key pair. Jul 25, 2016 For the Key Pair, click New. Choose the Key Type - RSA or ECDSA. (Refer to Appendix A in order to understand the differences between them.) Click the Enter new key pair name radio button. Distinctly identify the key pair name for recognition purposes. Choose the Key Size. Also, if you use RSA, choose General Purpose for Usage. Click Generate Now. The key pair should now be created.

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.

  1. Now at command line you can fix this with a ‘Crypto Key Generate RSA Modulus 2048‘ command, but you can’t get to command line only ASDM. On older versions of the ASDM you could generate the keypair in the Identification Certificates section (well you still can but only if you are also generating a certificate request file).
  2. SSH on the Cisco ASA requires the generation of a RSA keypair on the ASA. It is used to uniquely identify the ASA when the SSH client tries to establish a SSH connection to the SSH server (the ASA). To generate RSA key pairs for identity certificates, use the crypto key generate rsa command.

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. Windows 7 pro oem key. 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.

Q: I have a Cisco switch in my network, which I can access by hooking up a console cable directly to the device. I like to access the switch remotely using SSH. How can I enable ssh on my Cisco 3750 Catalyst Switch?
A: By default, when you configure a Cisco device, you have to use the console cable and connect directly to the system to access it. Follow the steps mentioned below, which will enable SSH access to your Cisco devices. Once you enable SSH, you can access it remotely using PuTTY or any other SSH client.

1. Setup Management IP

First, make sure you have performed basic network configurations on your switch. For example, assign default gateway, assign management ip-address, etc. If this is already done, skip to the next step.

In the following example, the management ip address is set as 192.168.101.2 in the 101 VLAN. The default gateway points to the firewall, which is 192.168.101.1

2. Set hostname and domain-name

Next, make sure the switch has a hostname and domain-name set properly.

Generate Rsa Crypto Key Cisco

Generate Rsa Key Pair Cisco Asa

3. Generate the RSA Keys

Rsa Key Pair Cisco

The switch or router should have RSA keys that it will use during the SSH process. So, generate these using crypto command as shown below.

Also, if you are running on an older Cisco IOS image, it is highly recommended that you upgrade to latest Cisco IOS.

4. Setup the Line VTY configurations

Setup the following line vty configuration parameters, where input transport is set to SSH. Set the login to local, and password to 7.

If you have not set the console line yet, set it to the following values.

5. Create the username password

If you don’t have an username created already, do it as shown below.

Note: If you don’t have the enable password setup properly, do it now.

Make sure the password-encryption service is turned-on, which will encrypt the password, and when you do “sh run”, you’ll seee only the encrypted password and not clear-text password.

5. Verify SSH access

From the switch, if you do ‘sh ip ssh’, it will confirm that the SSH is enabled on this cisco device.

After the above configurations, login from a remote machine to verify that you can ssh to this cisco switch.

In this example, 192.168.101.2 is the management ip-address of the switch.

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