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Basic Config­uration

Router­(co­nfig)# hostname R1
set hostname of Router
Router­(co­nfig)# no ip domain­-lookup
disable dns lookup
Router­(co­nfig)# enable secret class
set password for privileged EXEC mode
Router­(co­nfi­g-l­ine)# password cisco
sets console password
Router­(co­nfi­g-l­ine)# login
enables login
Router­(co­nfig)# copy run start
copies running config­uration to startup config­uration


Topology for and

Verify OSPF

Router# show ip ospf
shows all ospf inform­ation
Router# show ip ospf neighbor
shows ospf neighbor routers
Router# show ip route ospf
verify ospf networks
Router# show ip protocols
verify ospf config­uration
Router# show ip ospf interface
shows summary of OSPF-e­nabled interfaces
Router# show ip ospf interface F0/0
shows ospf inform­ation about that interface
For OSPFv3 add ipv6 to the command: Router­(co­nfig)# show ipv6 route ospf

Configure OSPF

Router­(co­nfig)# router ospf 1
enable ospf with specific process id
Router­(co­nfi­g-r­outer)# network 192.16­8.1.0 area 0
configure network with area id 0
Router­(co­nfi­g-r­outer)# router-id
set router id manually
Router­(co­nfi­g-r­outer)# auto-cost refere­nce­-ba­ndwith 10000
change default reference bandwith
Router­(co­nfig)# clear ip ospf process
clears ospf to refresh everything (f.e after set router-id)
Router­(co­nfig)# passiv­e-i­nte­rface F0/0
routing updates won't send on that interface
Router­(co­nfig)# no-pas­siv­e-i­nte­rface F0/0
router will send OSPF routing updates on that interface
Router­(co­nfi­g-if)# ip ospf cost 1565
set cost on a interface
Router­(co­nfi­g-if)# ip ospf priority 255
configure interface with ospf priority
Router­(co­nfi­g-if)# ip ospf priority 0
router can not be become DR or BDR


Topology for


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