Category: CCNA Study Guide

Command Interface Loopback Use This command creates a logical interface on the router. These are handy from an administrative perspective because the loopback interface will also stay in a up/up state unless you shutdown the interface. Syntax Router(config)#interface loopback <num> Example In this example, we will create a …

Command Access-list (Extended) Use This command is used to create a list that matches packets on a given criteria. While access-lists are most commonly associated with security, there are numerous uses. Extended lists match on source addresses and destination addresses as well as protocol information. Syntax Router(config)#access-list <100-199 …

Command IP Name Server Use This command allows you to set which DNS server the router will query when trying to resolve domain names. Syntax Router(config)#ip name-server <name> Example In this example we configure the ip name-server command to allow a router to resolve hostnames. 2611XM(config)#ip name-server 10.10.2.1 …

Command IP Domain-name Use This command allows you to set a domain name for the router. Syntax Router(config)#ip domain-name <name> Example In the below example, we set R1 to have a domain name of “cisco.com”. R1(config)#ip domain-name cisco.com Now if we check show cdp neighbors on R2 we …

Command IP Default Gateway Use This command allows the router to maintain routing functionality when it stops being a router. What that means is that, after a router crashes, it falls back to basic switching functionality. The default-gateway is where the router will send all packets. Syntax Router(config)#ip …

Command Username Use Creates a new user on the router. Syntax Router(config)#username <WORD> password <WORD> Example In the following example a new user is created on the router. This user is then used when logging in via a telnet session from R2. R1(config)#username Test password cisco Telnet is …

Command Default Interface Use This command allows you to quickly revert an interface back to its default configuration. If you have a lot of changes, this is much faster than using the no version of every command on the interface. Syntax Router(config)#default interface <interface> Example In this example …

Command Alias Exec Use This command is used to create shortcuts to various commands. While it is definately handy in the real world, we would not recommend using alias exec while studying for the CCNA, as you could potentially get more used to your own commands instead of …

Command Hostname Use Sets the hostname of the router. Syntax Router(config)#hostname <WORD> Example In the below example the hostname command is used to change the router name. R1(config)#hostname TEST TEST(config)#hostname R1 R1(config)#

Command IP nat inside source list Use This command is used to specify an access-list that matches which IPs should be translated. Syntax R1(config)#ip nat inside source list <access-list> <pool or interface> overload Options <pool> Specifies what NAT Pool to use. <interface> Tells NAT to use the IP …