Haven't had a chance to test this in a lab yet - Reading the OSPF design guide and have a query.

If I have 4 routers all using plain text authentication on the same LAN Segment but using two different passwords. Router 1 and 2 have same password, Router 3 and 4 have same password. Will I 1 and 2 become adjacent, and will 3 and 4 also? 

Router 1
interface Ethernet0
ip address 10.10.10.1 255.255.255.0
ip ospf authentication-key PASSWORD1

router ospf 10
network 10.10.10.1 0.0.0.0 area 0
area 0 authentication

Router 2
interface Ethernet0
ip address 10.10.10.2 255.255.255.0
ip ospf authentication-key PASSWORD1

router ospf 10
network 10.10.10.2 0.0.0.0 area 0
area 0 authentication

Router 3
interface Ethernet0
ip address 10.10.10.3 255.255.255.0
ip ospf authentication-key PASSWORD2

router ospf 10
network 10.10.10.3 0.0.0.0 area 0
area 0 authentication

Router 4
interface Ethernet0
ip address 10.10.10.4 255.255.255.0
ip ospf authentication-key PASSWORD2

router ospf 10
network 10.10.10.4 0.0.0.0 area 0
area 0 authentication