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Cisco Crypto Key Generate Rsa Modulus 2048

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

The key pair generation command should possibly be done as “exportable” – for transferring the keys to another router later, if the need arises to replace the old box & etc. E.g.: crypto key generate rsa general-keys Label GDKey modulus 2048 exportable. PuTTY: PuTTY Fatal Error: Server unexpectedly closed network connection. SecureCRT: Connection closed. OSX/Linux: sshexchangeidentification: Connection closed by remote host. 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. Crypto key generate rsa exportable label ipsec modulus 2048 crypto ca trustpoint tpipsec2017 enrollment terminal pem crl optional fqdn rtr.example.net rsakeypair ipsec subject-name C=BE,ST=city,L=area,O=Private,OU=Familly,CN=rtr.example.net crypto ca enroll tpipsec2017! Save the csr and submit to CA crypto ca authenticate tpipsec2017. Generate a 2048-bit rsa keypair: seclab-3650 ( config)#crypto key generate rsa modulus 2048 label 2048-bit-key 2. Create a trustpoint specifying self-signed enrollment and telling the TP to use that keypair.

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

Cisco Crypto Key Generate Rsa Modulus 2048 Price

1 Setup Local VTY line User ID and password

router (Config) # Line VTY 0 15

router (Config-line)# login local Download network signal speed booster for android.

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

Cisco rsa keyGenerate

router (Config)# crypto key generate rsa

how many bits in the modulus [512] :1024

router (Config)# ip ssh version2

Cisco Crypto Key Generate Rsa Modulus

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.”

Cisco Crypto Key Generate Rsa Modulus 2048 Download

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.

Cisco Switch Generate Rsa Key

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.

Crypto Key Generate Rsa Command

Syntax Description : Optional Strings to embed with SSH Crypto key

Crypto Key Generate Rsa 2048

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.