Hi rene
I did " clear ip ospf process " after adding loopback ip .But my router ID did not change
R1#clear ip ospf process
Reset ALL OSPF processes? [no]: yes
R1#
R1#show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 192.168.23.2
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.23.0 0.0.0.255 area 0
Routing Information Sources:
Gateway Distance Last Update
Distance: (default is 110)
Thanks