O'Reilly logo

ScreenOS Cookbook by Sunil Wadhwa, Joe Kelly, Ken Draper, David Delcourt, Vik Davar, Stefan Brunner

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

16.11. Configure OSPF on Point-to-Multipoint Links

Problem

You want to configure VPN on a point-to-multipoint interface terminating VPN tunnels, such as on a hub security gateway.

Solution

Configure all interfaces in the point-to-multipoint network cloud with the IP addresses in the same network:

	FIREWALL-B-> set interface tunnel.1 ip 10.0.10.1/24
	FIREWALL-A-> set interface tunnel.1 ip 10.0.10.2/24
	FIREWALL-C->set interface tunnel.1 ip 10.0.10.3/24

Configure the hub interface, which is given here on FIREWALL-B as a point-to-multipoint interface:

	FIREWALL-B-> set interface tunnel.1 protocol ospf area 0.0.0.0
	FIREWALL-B-> set interface tunnel.1 protocol ospf link-type p2mp
	FIREWALL-B->set interface tunnel.1 protocol ospf enable

Configure OSPF on the spoke firewalls:

	FIREWALL-A-> set interface tunnel.1 protocol ospf area 0.0.0.0
	FIREWALL-A-> set interface tunnel.1 protocol ospf enable

	FIREWALL-C-> set interface tunnel.1 protocol ospf area 0.0.0.0
	FIREWALL-C->set interface tunnel.1 protocol ospf enable

Discussion

Unlike nonbroadcast multiaccess (NBMA) networks, which ScreenOS does not support, there is no DR or BDR in a point-to-multipoint cloud. In fact, point-to-multipoint interfaces in OSPF are an emulation of multiple point-to-point links. On a point-to-multipoint interface, messages are replicated for each link automatically. Point-to-multipoint links need an IP address and cannot be unnumbered.

Figure 16-4 shows a point-to-multipoint topology. FIREWALL-B is the hub and FIREWALL-A and ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required