Contents
What are the mechanism used in OSPF?
OSPF offers a very distinguishable feature named: Routing Areas. It means dividing routers inside a single autonomous system running OSPF, into areas where each area consists of a group of connected routers. The idea of dividing the OSPF network into areas is to simplify administration and optimize available resources.
How Neighborship is formed in OSPF?
To establish OSPF full adjacency, two neighbor routers must be in the same area. Any individual interface can only be attached to a single area. If the address ranges specified for different areas overlap, IOS will adopt the first area in the network command list and ignore subsequent overlapping portions.
Which algorithm is used in OSPF?
shortest path first (SPF)
OSPF uses the shortest path first (SPF) algorithm to determine routes that should be added to the routing table. OSPF routers maintain a map of the internetwork called the link state database.
What are the stages of OSPF?
OSPF routers go through the seven states, called Down, Attempt/Init, Two ways, Exstart, Exchange, Loading and full while building adjacency with other OSPF speaking routers.
Does OSPF support classless?
OSPF supports the Classless Inter-Domain Routing (CIDR) addressing model. OSPF is a widely used IGP in large enterprise networks.
What is the flaw in the OSPF protocol?
The flaw lies in the OSPF protocol itself which allows uncompromised routers to be tricked into propagating false router-table updates known as link state advertisements or LSAs. The attack is such that the false tables persist over time.
How does a router create an OSPF packet?
Router R3 creates an OSPF packet (refer to Figure 1) with the new subnet 11.11.11.0/24 and sends it to the other routers in that same OSPF area. The created packet is called a link-state advertisement (LSA) packet. An attacker could mimic any router in the network, create a LSA packet, and falsify the neighbor router’s routing table.
Is there a way to close the vulnerability in OSPF?
Typically large corporations, universities and ISPs run autonomous systems. The only remedies are using another protocol such as RIP or IS-IS or changing OSPF to close the vulnerability, says Gabi Nakibly, a researcher at Israel’s Electronic Warfare Research and Simulation Center, who discovered the problem.
Can a malicious attacker join the open shortest path ( OSPF )?
An attacker does not have to join the Open Shortest Path First (OSPF) neighborhood routers. Instead, the attacker could be stealthy and sniff the network, crafting a malicious packet to tamper with the routing table. Let’s dive into an attacker’s potential path and how to control the routing table with a single packet using LogRhythm NetMon.