OSPF can be configured in VPNs for hub and spoke enviroments, even if its just one spoke.

• OSPF is configured as P2MP:

set protocols ospf area 0.0.0.0 interface st0.0 interface-type p2mp

set protocols ospf area 0.0.0.0 interface st0.0 metric 2000

set protocols ospf area 0.0.0.0 interface st0.0 retransmit-interval 5

• Tunnel interface has next-hop-tunnel is configured:

set interfaces st0 unit 0 family inet next-hop-tunnel 10.10.10.20 ipsec-vpn VPN

set interfaces st0 unit 0 family inet address 10.10.10.1/24

• The adjacency for st0.0 does not appear at all in "show ospf neighbors", no even an entry init status, and if traceoptions are configured, we can see that a Hello packet is arriving from the peer, and that is being dropped due to "mask mismatch" even though the mask is correctly configured:

OSPF packet ignored: netmask 255.255.255.0 mismatch from 10.10.10.20 on intf st0.0 area 0.0.0.0

Add "multipoint" statement to the tunnel interface:

set interfaces st0 unit 0 multipoint