The Need for Intrusion Detection
The need for intrusion detection is based on the increasing number of threats faced by the computer networks in today's world. Here are some of the fundamental reasons why so many attacks are being launched on computer networks: Computer networks are used to carry information that is valuable not only to the intended receiver but can also be valuable to anyone else who gets his or her hands on it. Therefore, computer networks are an important source of information theft. Thi..
This final section of the chapter summarizes some of the core SNMP concepts and details, particularly with regard to features of different SNMP versions. The Simple Network Management Protocol (SNMP), or more formally, the Internet Standard Management Framework, uses a structure in which the device being managed (the SNMP agent) has information that the management software (the SNMP manager) wants to display to someone operating the network. Each SNMP agent keeps a database,..
Tracking OSPF Advertisements Through a Network
When troubleshooting an OSPF issue, tracking the path of OSPF advertisements can be valuable in determining why certain entries are in a router’s RIB. As an example, notice network 192.168.1.0/24 in the topology provided in Figure 7-3, and consider how this network is entered into the RIB of the other OSPF routers. The following steps describe how network 192.168.1.0/24, which is directly connected to router R1, is learned by the RIB of routers R2, R3, and R4. Step 1. Rout..
Using BPDU Filtering to Disable STP on a Port
Ordinarily, STP operates on all switch ports in an effort to eliminate bridging loops before they can form. BPDUs are sent on all switch ports—even ports where PortFast has been enabled. BPDUs also can be received and processed if any are sent by neighboring switches. You always should allow STP to run on a switch to prevent loops. However, in special cases when you need to prevent BPDUs from being sent or processed on one or more switch ports, you can use BPDU filte..
Routing Multicast Traffic with PIM-SM and BSR
We've already discussed how PIM-SM requires a Rendezvous Point (RP) router. The most reliable way to achieve this is to have the network automatically discover the RP. This way, if the RP fails, another can automatically take over for it. We recommend using the Bootstrap Router (BSR) mechanism to dynamically distribute RP information. There are two different types of router configurations for this type of network. Most of the routers will support end devices, both group memb..
