Cisco OSPF – Change Router ID Without Reload

ciscoospfrouterrouting

We have setup OSPF on router and initial it pick ip address 70.xx.xx.33 but later we remove those IPs and reconfigure for new subnet but still OSPF showing older router ID sometime it's confusing seeing older IP address in Router ID, Is there a way i can tell OSPF re-initialize new ID without reload? 

R1#sh ip ospf summary-address

            OSPF Router with ID (70.xx.xx.33) (Process ID 1)

EDIT:

Its Cisco C3850 L3 switch with latest IOS running.

Best Answer

You didn't say what model router you have, but assuming a Cisco router (from the configuration example you have) can use the clear ip ospf process command to clear and reload OSPF on a router.

Check the Cisco Documentation:

clear ip ospf

To clear redistribution based on the OSPF routing process ID, use the clear ip ospf command in privileged EXEC mode.

clear ip ospf [pid] {process | redistribution | counters [neighbor [neighbor-interface] [neighbor-id]]}

Syntax Description - enter image description here

Usage Guidelines

Use the pid option to clear only one OSPF process. If the pid option is not specified, all OSPF processes are cleared.

Examples

The following example clears all OSPF processes:

clear ip ospf process
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