# Cisco Basic Commands

| **Command** | **Description** |
| --- | --- |
| **enable** | Moves a user from user exec mode into Privileged EXEC mode. Privileged exec mode is indicated by the # symbol in the command prompt. |
| **configure terminal** | Logs the user into Global Configuration mode |
| **interface** *fastethernet/number* | Enters interface configuration mode for the specified fast ethernet interface |

| **Basic Configuration Commands List** |  |
| --- | --- |
| **reload** | Reboots the Cisco switch or router |
| **hostname** *name* | Sets a host name to the current Cisco network device |
| **copy** *from-location to-location* | Copies files from one file location to another |
| **copy running-config startup-config** | Replaces the startup config with the active config when  the Cisco network device initializes |
| **copy startup-config running-config** | Merges the startup config with the currently active config in RAM |
| **write erase** |  |
| **erase startup-config** | Deletes the startup config |
| **ip address** *ip-address mask* | Assigns the specified IP address and subnet mask |
| **shutdown** |  |
| **no shutdown** | Shuts the interface down (shutdown) or brings it up (no shutdown) |
| **ip default-gateway** *ip\_address* | Sets the default gateway on the Cisco device |
| **show running-config** | Displays the current configuration of the device |
| **show startup-config** | Displays the saved configuration stored in the device's NVRAM, which will be loaded when the device starts up |
| **description** *string* | Assigns the specified description to an interface |
| **show running-config interface** *interface slot/number* | Displays the running configuration for the specified interface |
| **show ip interface** *\[type number\]* | Displays the status of a network interface as well as a detailed listing of its IP configurations and related characteristics. |
| **ip name-server** *serverip-1 serverip-2* | Sets the IP address of or more DNS servers that the device can use to resolve hostnames to IP addresses. |
|  |  |
| **Troubleshooting Cisco Commands List** |  |
| **ping** \*{hostname | system-address} \[source source-address\]\* |
| **speed** \*{10 | 100 |
| **duplex** \*{auto | full |
| **cdp run** |  |
| **no cdp run** | Enables or disables Cisco Discovery Protocol (CDP) for the device |
| **show mac address-table** | Displays the MAC address table |
| **show cdp** | Shows whether CDP is enabled globally |
| **show cdp neighbors**\*\[detail\]\* | Lists summary (or detailed) information about each neighbor connected to the device |
| **show interfaces** | Displays detailed information about interface status, settings and counters |
| **show interface status** | Displays the interface line status |
| **show interfaces switchport** | Displays many configuration settings and current operational status, including VLAN trunking details |
| **show interfaces trunk** | Lists information about the currently operational trunks and the VLANs supported by those trunks |
| **show vlan** |  |
| **show vlan brief** | Lists each VLAN and all interfaces assigned to that VLAN but does not include trunks |
| **show vtp status** | Lists the current VLAN Trunk Protocol (VTP) status, including the current mode |
|  |  |
| **Routing and VLAN Commands** |  |
| **show ip route** | Displays the current state of the IP routing of all known routes that are either statically configured or learned dynamically through a routing protocol |
| **ip route** \*network-number network-mask {ip-address | interface}\* |
| **router rip** | Enables a Routing Information Protocol (RIP) routing process, which places you in router configuration mode |
| **network** *ip-address* | Associates a network with a RIP routing process |
| **version 2** | Configures the software to receive and send only RIP version 2 packets |
| **no auto-summary** | Disables automatic summarization |
| **default-information originate** | Generates a default route into RIP |
| **passive-interface** *interface* | Sets the specified interface to passive RIP mode, which means RIP routing updates are accepted by, but not sent out of, the interface |
| **show ip rip database** | Displays the contents of the RIP routing database |
| **ip nat** \*\[inside | outside\]\* |
| **ip nat inside source** \*{list{access-list-number | access-list-name}} interface type number\[overload\]\* |
| **ip nat inside source static** *local-ip global-ip* | Establishes a static translation between an inside local address and an inside global address |
| **vlan** | Creates a VLAN and enters VLAN configuration mode for further definitions |
| **switchport access vlan** | Sets the VLAN that the interface belongs to. |
| **switchport trunk encapsulation dot1q** | Specifies 802.1Q encapsulation on the trunk link. |
| **switchport access** | Configures a specific Ethernet port on a switch to operate in access mode to accommodate an end device such as a computer, server or printer. The port must then be assigned to a single VLAN. |
| **vlan vlan-id** *\[name vlan-name\]* | Configures a specific VLAN name (1 to 32 characters) |
| **switchport mode** \*{ access | trunk }\* |
| **switchport trunk** *{encapsulation { dot1q }* | Sets the trunk characteristics when the interface is in trunking mode. In this mode, the switch supports simultaneous tagged and untagged traffic on a port. |
| **encapsulation dot1q vlan-id** | Defines the matching criteria to map 802.1Q frames ingress on an interface to the appropriate service instance |
| **show spanning-tree** | Provides detailed information about the Spanning Tree protocol for all VLANs |
|  |  |
| **DHCP Commands** |  |
| **ip address dhcp** | Acquires an IP address on an interface via DHCP |
| **ip dhcp pool name** | Used to configure a DHCP address pool on a DHCP server and enter DHCP pool configuration mode |
| **domain-name** *domain* | Specifies the domain name for a DHCP client |
| **network** *network-number \[mask\]* | Configures the network number and mask for a DHCP address pool primary or secondary subnet on a Cisco IOS DHCP server |
| **ip dhcp excluded-address** *ip-address \[last-ip-address\]* | Specifies IP addresses that a DHCP server should not assign to DHCP clients |
| **ip helper-address** *address* | Enables forwarding of UDP broadcasts, including BOOTP, received on an interface |
| **default-router** *address\[address2 ... address8\]* | Specifies the default routers for a DHCP client |
|  |  |
| **Security Commands** |  |
| **password** *pass-value* | Lists the password that is required if the login command (with no other parameters) is configured |
| **username** *name* **password** *pass-value* | Defines one of possibly multiple user names and associated passwords used for user authentication. It is used when the **login local** line configuration command has been used |
| **enable password** *pass-value* | Defines the password required when using the **enable** command |
| **enable secret** *pass-value* | Sets the password required for any user to enter enable mode |
| **service password-encryption** | Directs the Cisco IOS software to encrypt the passwords, CHAP secrets and similar data saved in its configuration file |
| **ip domain-name** *name* | Configures a DNS domain name |
| **crypto key generate rsa** | Creates and stores (in a hidden location in flash memory) the keys that are required by SSH |
| **transport input** \*{telnet | ssh}\* |
| **access-list** \*access-list-number {deny | permit} source \[source-wildcard\] \[log\]\* |
| **access-class** | Restricts incoming and outgoing connections between a particular VTY (into a basic Cisco device) and the addresses in an access list |
| **ip access-list** \*{standard | extended} {access-list-name |
| **permit source** *\[source-wildcard\]* | Allows a packet to pass a named IP ACL. To remove a permit condition from an ACL, use the “no” form of this command. |
| **deny source** *\[source-wildcard\]* | Used to set conditions in a named IP ACL that will deny packets. To remove a deny condition from an ACL, use the “no” form of this command. |
| **ntp peer** *<ip-address>* | Configures the software clock to synchronize a peer or to be synchronized by a peer |
| **switchport port-security** | Enables port security on the interface |
| **switchport port-security maximum maximum** | Sets the maximum number of secure MAC addresses on the port |
| **switchport port-security mac-address** \*{mac-addr | {sticky \[mac-addr\]}}\* |
| **switchport port-security violation** \*{shutdown | restrict |
| **show port security** *\[interface interface-id\]* | Displays information about security options configured on the interface |
|  |  |
| **Monitoring and Logging Commands** |  |
| **logging** *ip address* | Configures the IP address of the host that will receive the system logging (syslog) messages |
| **logging trap level** | Used to limit messages that are logged to the syslog servers based on severity. Specify the number or name of the desired severity level at which messages should be logged |
| **show logging** | Displays the state of system logging (syslog) and the contents of the standard system logging buffer |
| **terminal monitor** | Sends a copy of all syslog messages, including debug messages, to the Telnet or SSH user who issues this command |