2.1 Basic Device Configuration

Configuring SSH access

SSH is an encrypted and secure way of remotely managing Cisco Devices. SSH is widely used instead of Telnet since Telnet is an unencrypted plain text-oriented protocol and passes data as plain text which can be easily readable by anyone.

Configuring Auto-MDIX

Configure the IP domain

S1(config)# ip domain-name [domain-name]

Generate RSA key pairs

S1(config)# crypto key generate rsa modulus [key-length]

[NOTE] The minimum RSA key length to be able to use SSH2 is 768 bits; As a recommendation we will set it to 1,024 bits

Add and Secure a User and grant privileges

S1(config-if)# user [username] privilege [rank] secret [password]

Configure Device’s VTY Lines and

S1(config)# line vty 0 15 

Set the input transport mode to use SSH only

S1(config-line)# transport input ssh

Require local authentication for SSH connections from the local user database

S1(config-line)# login local

Enable SSH version 2

S1(config-line)# ip ssh version 2
Switchport Duplex and Speed Configuration Example
s1> enable
S1# configure terminal
S1(config)# interface fa0/1
S1(config-if)# duplex auto
S1(config-if)# speed 1000
S1(config-if)# exit
S1(config)# 

[NOTE] Full-Duplex is always used when devices are operating at 1000Mbps/1Gpbs and/or Fiber-Optic 1000BASE-SX

Removing the existing RSA Key Pair

S1(config)# crypto key zeroize rsa

[NOTE] If the RSA key pair is deleted, the SSH will be automatically disabled.