Ccna Pcg Ch 10: Single Area Ospf

Front 1

Router(config)#router ospf 123

Back 1

Starts OSPF process 123. The process ID is any positive integer value between 1 and 65535. The process ID is not related to the OSPF area. The process ID merely distinguishes one process from another within the device

Front 2

Router(config-router)#network 17.16.10.0.0 0.0.0.255 area 0

Back 2

OSPF advertises interfaces, not networks. Uses the wildcard mask to determine which itnerfaces to advertise. Read this line to say "Any interface with an address of 172.16.10.x is to be put into area 0."

Front 3

Router(config=router)#log-adjacency-changes detail

Back 3

Configures the router to send a syslog message when there is a change of state between OSPF neighbors

Front 4

Router(config)#interface loopback 0

Back 4

Creates a virtual interface named loopback -, and then moves the router to interface configuration mode.

Front 5

router(config-router)#router-id 10.1.1.1

Back 5

Sets the router ID to 10.1.1.1

Front 6

Router(config-if)#ip ospf priority 50

Back 6

Changes the OSPF interface priority to 50.

Front 7

Router(config-if)#bandwidth 128

Back 7

If you change the bandwidth, OSPF recalculates the cost of the link

Front 8

Router(config-if)#ip ospf cost 1564

Back 8

Changes the cost to a value of 1564

Front 9

Router(config-router)#area 0 authentication

Back 9

Enables simple authentication; password will be sent in clear text

Front 10

Router(config-if)#ip ospf authentication-key fred

Back 10

Sets key (password)to fred

Front 11

Router(config-router)#area 0 authentication message-digest

Back 11

Enables authentication with MD5 password encryption

Front 12

Router(config-if)#ip ospf message-digest-key 1 md5 fred

Back 12

1 is the key.id this value must be the same as that of your neighboring router. md5 indicates that the MD5 hash algorithm will be used

Front 13

router(config-if)#ip ospf hello-interval timer 20

Back 13

Changes the Hello Interval timer to 20 seconds.

Front 14

Router(config-if)#ospf dead-interval 80

Back 14

Changes the dead interval timer to 80 seconds.

Front 15

Router(config-router)#default-information originate

Back 15

Sets the default route to be propagated to all OSPF routers.

Front 16

Router(config-router)#default-information originate always

Back 16

The always option propagates a default "quad=zero" route even if one is not configured on this router.

Front 17

Router#show ip ospf interface

Back 17

Displays OSPF info as it relates to all interfaces

Front 18

Router#show ip ospf interface

Back 18

Displays OSPF info as it relates to all interfaces

Front 19

show ip ospf border-routers

Back 19

Displays border and boundary router information

Front 20

Router#show ip ospf neighbor

Back 20

lists all ospf neighbors and their states

Front 21

Router#show ip ospf neighbor detail

Back 21

displays a detailed list of neighbors

Front 22

Router#show ip ospf database

Back 22

displays contents of the OSPF database

Front 23

Router#show ip ospf database nssa-external

Back 23

Displays NSSA external link states

Front 24

Router#clear ip route *

Back 24

Clears entire routing table.

Front 25

Router#clear ip route a.b.c.d

Back 25

clears specific roue to network a.b.c.d

Front 26

Router#clear ip opsf counters

Back 26

resets ospf counters

Front 27

router#clear ip ospf process

Back 27

Resets entire ospf process, forcing ospf to recreate neighbors, database, and routing table

Front 28

Router#debug ip ospf events

Back 28

Displays all ospf events

Front 29

Router#debug ip ospf adjacency

Back 29

Displays various OSPF states and DR/BDR election between adjacent routers

Front 30

Router#debug ip ospf packets

Back 30

Displays OSPF packets