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.

• Cisco 3560 8 Port
• Cisco 3560 Data Sheet

May 20, 2014 Author, teacher, and talk show host Robert McMillen shows you how to use the Cisco ASA version 9 generate RSA keys command. May 20, 2014  Author, teacher, and talk show host Robert McMillen shows you how to use the Cisco ASA version 9 generate RSA keys command.

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.

3. Generate the RSA Keys

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.

Cisco 3560 8 Port

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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Cisco 3560 Data Sheet

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• 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 Aes 128 random key generator.

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.

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