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,..
Verifying AppleTalk Connectivity and Troubleshooting
The IOS software offers numerous tools to aid the network administrator in tracking down AppleTalk connectivity problems, network configuration errors, and dynamic routing protocol problems. In this section, we examine IOS EXEC show commands, debug commands, and diagnostic commands that facilitate identifying network issues. As previously examined, the IOS EXEC command show appletalk interface is a useful tool for identifying network number and zone name misconfigurations, a..
Local Management Interface (LMI) messages manage the local access link between the router and the Frame Relay switch. A Frame Relay DTE can send an LMI Status Enquiry message to the switch; the switch then replies with an LMI Status message to inform the router about the DLCIs of the defined VCs, as well as the status of each VC. By default, the LMI messages flow every10 seconds. Every sixth message carries a full Status message, which includes more complete status informatio..
Enhanced IGRP and Distribute-List
A distribution list is used to block routing information from being sent or received. This list can be applied on a per-routing protocol basis or a per-interface basis. When applied on a per-routing protocol basis, the distribution list will block all routing updates that are exiting or entering the protocol that do not pass the access-list. For example, consider this code: router eigrp 1 network 10.0.0.0 distribute-list 1 in access-list 1 deny 10.10.10.0 0.0.0.255 a..
