HP 445946-001 - Manual (Page 116)

Routing Information Protocol
116
Multicast
RIPv2 messages use IP multicast address (224.0.0.9) for periodic broadcasts. Multicast RIPv2
announcements are not processed by RIPv1 routers. IGMP is not needed since these are inter-router
messages which are not forwarded.
To configure RIPv2 in RIPv1-compatibility mode, set multicast to
disable
.
Default
The RIP router can listen and supply a default route, usually represented as 0.0.0.0 in the routing table.
When a router does not have an explicit route to a destination network in its routing table, it uses the
default route to forward those packets.
Metric
The metric field contains a configurable value between 1 and 15 (inclusive) which specifies the current
metric for the interface. The metric value typically indicates the total number of hops to the destination.
The metric value of 16 represents an unreachable destination.
Authentication
RIPv2 authentication uses plaintext password for authentication. If configured using Authentication
password, then it is necessary to enter an authentication key value.
The following method is used to authenticate a RIP message:
• If the router is not configured to authenticate RIPv2 messages, then RIPv1 and unauthenticated RIPv2
messages are accepted; authenticated RIPv2 messages are discarded.
• If the router is configured to authenticate RIPv2 messages, then RIPv1 messages and RIPv2 messages
which pass authentication testing are accepted; unauthenticated and failed authentication RIPv2
messages are discarded.
For maximum security, RIPv1 messages are ignored when authentication is enabled (
cfg/l3/rip/if
x/auth password
); otherwise, the routing information from authenticated messages is propagated by
RIPv1 routers in an unauthenticated manner.