Cisco commands basics

Check all interface brief

Router# show ip interface brief

Changing DHCP:

Router(config)# ip dhcp pool DHCP-POOL 
Router(config-dhcp)# no dns-server
Router(config-dhcp)# dns-server “another DNS server IP”
Router(config-dhcp)# exit

Adding/changing Interface IP

Configure the Fast Ethernet WAN Interface

This procedure applies only to the Cisco 851 and Cisco 871 router models. Perform these steps to configure the Fast Ethernet interface, beginning in global configuration mode:


Step 1

interface type number
Router(config)# interface fastethernet 4

Enters the configuration mode for a Fast Ethernet WAN interface on the router.

Step 2

ip address ip-address mask
Router(config-int)# ip address

Sets the IP address and subnet mask for the specified Fast Ethernet interface.

Step 3

no shutdown
Router(config-int)# no shutdown

Enables the Ethernet interface, changing its state from administratively down to administratively up.

Step 4

Router(config-int)# exit

Exits configuration mode for the Fast Ethernet interface and returns to global configuration mode.

Make full backup of Flash when there is multiple files

WLC5760#archive tar /create tftp:// flash:

Use a TFTP Server to Backup and Restore a Configuration

This is a step-by-step approach to copy a configuration from a router to a TFTP server, and back to another router. Before you proceed with this method, make sure you have a TFTP server on the network to which you have IP connectivity.

  1. At the Router> prompt, issue the enable command, and provide the required password when prompted.The prompt changes to Router#, which indicates that the router is now in privileged mode.
  2. Copy the running configuration file to the TFTP server:
    CE_2#copy running-config tftp:
    Address or name of remote host []?
    Destination filename [ce_2-confg]? backup_cfg_for_my_router
    1030 bytes copied in 2.489 secs (395 bytes/sec)
  3. Open the configuration file with a text editor. Search for and remove any line that starts with “AAA”.Note: This step is to remove any security commands that can lock you out of the router.
  4. Copy the configuration file from the TFTP server to a new router in privileged (enable) mode which has a basic configuration.
    Router#copy tftp: running-config
    Address or name of remote host []?
    Source filename []? backup_cfg_for_my_router
    Destination filename [running-config]?
    Accessing tftp://
    Loading backup_cfg_for_router from (via FastEthernet0/0): !
    [OK - 1030 bytes]
    1030 bytes copied in 9.612 secs (107 bytes/sec)

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