There are several ways to access the Cisco router for configuration and management. We can access the router via console, SSH, telnet and Aux interfaces.
Cisco Router Console
Consol port provides Out-of-band access for management a Cisco router. Consol required physical presence for accessing the router. This port is the most important port, therefore each Cisco router and switch must contain console port.
The console port connects a computer directly to a router or switch. The console cable is necessary for initial configuration of a Cisco device. Because there is no more SSH, HTTP, HTTPS and telnet configured initially to connect the router.
The console cable connects a computer to the router via the console port. The figure below illustrates the console port as well as console cable. A console cable is a special cable. One end of the cable is the RJ49 type and a DB9 to the RJ45 converter moulded on the other end.
Secure Socket Shell (SSH)
SSH is a network protocol providing secure remote access for the management of network devices. It provides CLI connection through a virtual interface, over a network. It also provides strong authentication and encryption. Many network administrator uses SSH for managing systems remotely. SSH connections must active networking services on the device including an active interface configured with an IP address so SSH required in-band connection method
A Telnet is another remote access method just like SSH but it is an insecure method. telnet establishing a CLI session through a virtual interface, over a network. Telnet does not give a securely encrypted connection. User authentication, passwords, and commands are sending over the network in plain text. Telnet is also the in-band connection method.
Some routers may also support a legacy auxiliary port to set up a CLI session remotely using a modem. Similar to a console connection, the AUX port is also provided out-of-band connection and does not need networking services to be configured or available.
Generally, the putty software provides remote connectivity over different protocol and different way. Putty is a third-party software which is download here