Penetration testing is divided into the following five stages: 1. Reconnaissance 2. Scanning 3. Obtaining access 4. Maintaining access 5. Erasing evidence In the reconnaissance phase, the tester attempts to gather as much information as possible about the selected target. Reconnaissance can be both active and passive. In an active reconnaissance attack, the tester uses tools such as..
Link-state packets are divided into two types: level 1 and level 2. Level 2 packets contain information about all the reachable prefixes within the IS-IS domain. The topology for level 1 packets is known for the local area only, so these packets are included in the level 1 LSP. Individual LSPs are identified by four components of the LSP header. These include the LSP ID, the sequence number, the checksum, and the remaining lifetime. LSP ID is divided into the source ID, the P..
Three Steps of Initial STP Convergence
This section considers the algorithm that the Spanning-Tree Protocol uses to initially converge on a loop-free logical topology. Although there are many facets to the Spanning-Tree Protocol, the initial convergence can be broken down into three simple steps: • Elect one Root Bridge • Elect Root Ports • Elect Designated Ports When the network first starts, all of the bridges are announcing a chaotic mix of BPDU information. However, the bridges..
If you have several physical interfaces on your router that you want to treat as a single dialer, particularly for PPP multilink channel bonding, you can create a logical dialer interface: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#interface BRI0/0 Router1(config-if)#encapsulation ppp Router1(config-if)#dialer pool-member 1 Router1(config-if)#isdn switch-type basic-ni Router1(config-if)#isdn spid1 8005551234..
Using MSDP to Discover External Sources
The typical way to configure Multicast Source Discovery Protocol (MSDP) involves first selecting one of your MBGP routers as the RP for your internal network. Then you set up an MSDP peer relationship with the RP in another Autonomous System, which is usually an MBGP peer router in the next domain. The following configuration includes commands required to configure the router as an RP for the internal network using BSR: Router-ASBR1#configure terminal Enter configuration c..
