Juniper IGP - CONFIGURATION GUIDE V11.1.X Configuration Manual page 317

route to reach the remote neighbor. A best route to the neighbor must exist in the
IP routing table.
You must explicitly configure a remote neighbor on an OSPF router. You must specify
the remote neighbor with which the router forms an adjacency and the source IP
address the router uses for OSPF packets destined to its peer remote neighbor.
To form an adjacency with its remote neighbor, all OSPF packets are sent to the
remote neighbor as unicast packets with the destination IP address equal to the
source IP address of the remote neighbor. Use the update-source loopback command
to assign the source IP address to a remote neighbor.
The connection between two remote neighbors is treated as an unnumbered
point-to-point link that resides in the same area as that to which the pair of remote
neighbors belongs.
The rules of OSPF adjacency must be followed for remote neighbors to form an
adjacency with each other; for example, the neighbors must be in the same OSPF
area and have the same hello interval and dead interval, and so on.
After you have used the remote-neighbor command to specify the remote neighbors
and the update-source loopback to assign the source IP address, you must set a TTL
value with the ttl command, because a remote neighbor can be more than one hop
away. Configuration of all other remote-neighbor attributes is optional.
authentication-key
authentication message-digest
authentication-none
Use to enable simple password authentication and assign a password for
communication with OSPF remote neighbors.
Example
host1(config-router-rn)#authentication-key 0 br549hee
Use the no version to delete the password.
See authentication-key
Use to specify that MD5 authentication is to be used on the OSPF remote neighbor
interface.
Example
host1(config-router-rn)#authentication message-digest
There is no no version.
See authentication message-digest
Use to specify that no authentication is to be used on the OSPF remote neighbor
interface.
Example
Chapter 5: Configuring OSPF
293
Remote Neighbors