Therefore once MD5 authentication has been configured on Area 0 the virtual links require setting up for MD5.
NB:Done under the "router ospf" instance
R1
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
area 12 virtual-link 2.2.2.2 authentication
area 12 virtual-link 2.2.2.2 message-digest-key 1 md5 letme0
R2
area 12 virtual-link 1.1.1.1 authentication
area 12 virtual-link 1.1.1.1 message-digest-key 1 md5 letme0
area 23 virtual-link 3.3.3.3 authentication
area 23 virtual-link 3.3.3.3 message-digest-key 1 md5 letme0
R3
area 23 virtual-link 2.2.2.2 authentication
area 23 virtual-link 2.2.2.2 message-digest-key 1 md5 letme0
