Cisco router basic command and config

Show the hardware + software specifications of the router: show version

Show the current global configuration: show running-config

NAT

Enter the config mode  configure terminal   and only then add a static NAT rule: ip nat inside source static tcp <inside_local_ip> <port> <outside_global_ip> <port>

If you want to remove this NAT rule, run the same command but adding no at the beggining (in config mode as well!).

Refer to this article for more details.

Note: There are two main copies of Cisco Router configuration file. The configuration file where router stores the configuration changes when the router is up and running is called the “running-config” file. The “running-config” file is NOT persistent (stored in RAM), which means that the changes made in the “running-config” while the router is running are not retained after a reboot. To make it persistent after a reboot, we need to save it into the “startup-config” file using this command:

copy running-config startup-config 

Show interface

The show interface  command displays the status of the router’s interfaces. For a summary we can use show ip interface brief

SECURITY

Disable HTTP access to the Cisco router :

configure terminal
no ip http server