Prohibiting The Advertisement Of Networks; Generating A Default External Route (Asbr) - HP 7102dl - ProCurve Secure Router Configuration Manual

IP Routing—Configuring RIP, OSPF, BGP, and PBR
Configuring OSPF
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Prohibiting the Advertisement of Networks

You can prohibit an ABR from advertising networks in one area to routers in
another area. You can also prohibit the advertisement of only a certain range
of destinations within the area. Simply configure two route summaries for the
area: one for accessible networks with the advertise keyword and one for
prohibited networks with the not-advertise keyword.
For example, you could prohibit a router from advertising a summary link to
networks ranging from 192.168.1.0 to 192.168.63.0 with the following
command:
ProCurve(config-ospf)# area 1 range 192.168.0.0 255.255.192.0 not-advertise
As long as their ABR has a route to the network(s), hosts will still be able to
reach these networks using their default route. However, other routers will
not hold an actual route to the network(s).

Generating a Default External Route (ASBR)

An ASBR is a router on an OSPF network that also connects to an external
network. Typically, it runs both OSPF and an exterior gateway protocol.
However, because OSPF defines all non-OSPF routes as external, the ASBR
may simply be a WAN router with a default route that it redistributes into
OSPF.
The ASBR needs to somehow make the external routes that it learns available
to other OSPF routers. A common way of doing this is to advertise a default
route for external routes.
From the OSPF configuration mode context on the ASBR, enter this
command:
Syntax: default-information-originate [always] [metric <value>] [metric-type {1 | 2}]
The default route may come from one of three sources:
The routing table includes a static default route.
The router has received a default route from the external network. For
example, the WAN interface may receive an IP address and default route
from the remote router in the external network.
The router generates its own default route.