Imagine that you were asked by your neighbors to steal the bicycle of their child. The child does not know that you are going to attempt to steal it, but the parents want to judge how difficult it would be if someone were to try to steal it. You know that stealing is illegal, and you wonder if it is still wrong if the parents authorize you to do it. The parents ask you to do them this favor and tell them the results. Penetration testing is no different from this analogy. You ..
1701. The show isis database Command
The show isis database command shows the LSPs held in the local database. The LSP ID shows the system ID of the generating router and whether this LSP is from a router or a pseudonode. The last octet shows whether the LSP was too large to fit into one PDU; a nonzero value in this field indicates that this is a fragment of an LSP (the next number states the fragment number). Because IS-IS is a link-state protocol, the database should be identical on every router of the ..
Routing Policy and the BGP Decision Algorithm
A BGP router may receive paths for the same route from many neighbors. How the best path is selected is a matter of local policy. The policy within an AS must be consistent; otherwise, routing loops could occur. Conceptually, the policy and decision process is shown in Figure 11-16. Figure 11-16. BGP's Policy and Decision Process An incoming Routing Information Base is maintained for each peer. Incoming policy is applied to each RIB, and complying routes are p..
Viewing Frame Relay Status Information
There are several useful show commands for looking at Frame Relay circuits and virtual circuits. It is usually best to start at the physical layer and work upward through the protocol layers. You can look at the physical interface with the show interfaces command: Central#show interfaces Serial0 The show frame-relay pvc command allows you to see information about each of your Frame Relay PVCs: Central#show frame-relay pvc And sometimes it is also useful to look at the LM..
Before moving on to discuss how to influence route choices by changing the OSPF interface costs, first take a moment to consider the CPU-intensive SPF work done by a router. SPF does the work to piece together topology information to find all possible routes to a destination. As a result, SPF must execute when the intra-area topology changes, because changes in topology impact the choice of best route. However, changes to Type 3 LSAs do not drive a recalculation of the ..
