Crypto Key Generate Rsa Please Define A Domain Name First

R1(config)# ip domain-name ccie.com – To define a default domain name that the Cisco IOS software uses to complete unqualified host names. R1(config)# crypto key generate rsa – To generate RSA key pairs. The name for the keys will be: R1.ccie.com Choose the size of the key modulus in the range of 360 to 2048 for your General purpose keys.

router(config)# hostname R1
R1(config)# ip domain-name ccie.com
–> To define a default domain name that the Cisco IOS software uses to complete unqualified host names

R1(config)# crypto key generate rsa
–> To generate RSA key pairs

The name for the keys will be: R1.ccie.com
Choose the size of the key modulus in the range of 360 to 2048 for your General purpose keys. Choosing a key modulus
greater than 512 may take a few minutes

Most people believe that the ip domain-name command is required in order to generate a certificate. This is true if you don’t use the command label. Now see what happens if we try without it. C1801(config)#crypto key generate rsa modulus 1024% Please define a domain-name first. Sw1(config)#crypto key generate rsa% Please define a domain-name first. Create, delete, share, import, and export cryptographic keys. Providing the Public Key to Clients.(Without special-usage keys, one key is used for both authentication methods, increasing the exposure of that key.).

How many bits in the modulus [512]: 1024
–> modulus : determines the strength of the key , the higher the modulus number the strong the key is
the higher the modulus number the more CPU cycles you are going to have to use encrypt and decrypt

R1(config)# username edaoud privilege 15 secret cisco
–> To establish a username-based authentication system

R1(config)# line vty 0 4
–> for telnet per default, there is five lines, 0 to 4

R1(config-line)# login local
–> To enable password checking at login

R1(config-line)# transport input ssh
–> To define protocol SSH to be used to connect to a specific line of the router

Crypto Key Generate Rsa Please Define A Domain Name First Name

R1(config)# ip ssh version 2
–> Specify protocol version to be supported

/counter-strike-global-offensive-steam-key-generator-online.html. R1(config)# ip ssh time-out <0-120> ms
–> Specify SSH time-out interval

R1(config)# ip ssh authentication-retries <0-5>
–> Specify number of authentication retries

Crypto Key Generate Rsa Please Define A Domain Name First Word

R1(config)# ip ssh maxstartups
–> Max concurrent session allowed

R2# ssh -l edaoud 10.1.12.1
–> Specifies the user ID to use when logging in on the remote networking device that is running the SSH server.

router# show ssh
%No SSHv2 server connections running.
%No SSHv1 server connections running.

router# sh ip ssh
SSH Disabled – version 1.99
%Please create RSA keys to enable SSH (and of atleast 768 bits for SSH v2).
Authentication timeout: 120 secs; Authentication retries: 3
Minimum expected Diffie Hellman key size : 1024 bits
IOS Keys in SECSH format(ssh-rsa, base64 encoded): NONE

router# show control-plan host open-ports
router# show tcp

Below Quote are taken from CCIE Routing and Switching Exam Certification Guide 4th Edition.

Using Secure Shell Protocol

Telnethas long been used to manage network devices; however, Telnet traffic is sent in clear text. Anyone
able to sniff that traffic would see your password and any other information sent during the Telnet
session. Secure Shell (SSH) is a much more secure way to manage your routers and switches. It
is a client/server protocol that encrypts the traffic in and out through the vty ports.

Cisco routers and switches can act as SSH clients by default, but must be configured to be SSH
servers. That is, they can use SSH when connecting to another device, but require configuration
before allowing devices to connect via SSH to them. They also require some method of
authenticating the client. This can be either a local username and password, or authentication with
a AAA server (AAA is detailed in the next section).

There are two versions of SSH. SSH Version 2 is an IETF standard that is more secure than version
1. Version 1 is more vulnerable to man-in-the-middle attacks, for instance. Cisco devices support
both types of connections, but you can specify which version to use.
Telnet is enabled by default, but configuring even a basic SSH server requires several steps:
1. Ensure that your IOS supports SSH. You need a K9 image for this.
2. Configure a host name, unless this was done previously.
3. Configure a domain name, unless this was done previously.
4. Configure a client authentication method.
5. Tell the router or switch to generate the Rivest, Shamir, and Adelman (RSA) keys that will be
used to encrypt the session.
6. Specify the SSH version, if you want to use version 2.
7. Disable Telnet on the VTY lines.
8. Enable SSH on the VTY lines.

Example 18-4 shows a router being configured to act as an SSH server.

Crypto Key Generate Rsa Please Define A Hostname Other Than Router

Example 18-4 SSH Configuration
router(config)# hostname R3
R3(config)# ip domain-name CCIE2B
R3(config)# username cisco password Cisco
R3(config)# crypto key generate rsa
The name for the keys will be: R3.CCIE2B
Choose the size of the key modulus in the range of 360 to 2048 for your
General Purpose Keys. Choosing a key modulus greater than 512 may take
a few minutes.
How many bits in the modulus [512]: 1024
% Generating 1024 bit RSA keys …[OK]
R3(config)#
*May 22 02:06:51.923: %SSH-5-ENABLED: SSH 1.99 has been enabled
R3(config)# ip ssh version 2
!
R3(config)# line vty 0 4
R3(config-line)# transport input none
R3(config-line)# transport input ssh
R3(config-line)#^Z
!
R3# show ip ssh
SSH Enabled- version 2.0
Authentication timeout: 120 secs; Authentication retries: 3