Network+ Guide to Networks, Fourth EditionObjectivesWhat Are Integrity and Availability?What Are Integrity and Availability? (continued)Slide 5VirusesTypes of VirusesTypes of Viruses (continued)Slide 9Virus CharacteristicsVirus Protection: Antivirus SoftwareAntivirus PoliciesAntivirus Policies (continued)Virus HoaxesFault ToleranceEnvironmentPower: Power FlawsUPSs (Uninterruptible Power Supplies)UPSs (continued)GeneratorsTopology and ConnectivityTopology and Connectivity (continued)Slide 23Slide 24ServersServer MirroringClusteringStorage: RAID (Redundant Array of Independent (or Inexpensive) Disks)RAID Level 0―Disk StripingRAID Level 1—Disk MirroringRAID Level 1—Disk Mirroring (continued)RAID Level 3—Disk Striping with Parity ECCRAID Level 3—Disk Striping with Parity ECC (continued)RAID Level 5—Disk Striping with Distributed ParityRAID Level 5—Disk Striping with Distributed Parity (continued)NAS (Network Attached Storage)NAS (continued)SANs (Storage Area Networks)Data BackupBackup Media and MethodsOptical MediaTape BackupsExternal Disk DrivesNetwork BackupsBackup StrategyBackup Strategy (continued)Slide 47Slide 48Disaster Recovery: Disaster Recovery PlanningDisaster Recovery ContingenciesSummarySummary (continued)Slide 53Slide 54Network+ Guide to Networks, Fourth EditionChapter 13Ensuring Integrity and AvailabilityNetwork+ Guide to Networks, 4e 2Objectives•Identify the characteristics of a network that keeps data safe from loss or damage•Protect an enterprise-wide network from viruses•Explain network- and system-level fault-tolerance techniques•Discuss issues related to network backup and recovery strategies•Describe the components of a useful disaster recovery plan and the options for disaster contingenciesNetwork+ Guide to Networks, 4e 3What Are Integrity and Availability?•Integrity: soundness of network’s programs, data, services, devices, and connections•Availability: how consistently and reliably file or system can be accessed by authorized personnel–Need well-planned and well-configured network–Data backups, redundant devices, protection from malicious intruders•Phenomena compromising integrity and availability: –Security breaches, natural disasters, malicious intruders, power flaws, human errorNetwork+ Guide to Networks, 4e 4What Are Integrity and Availability? (continued)•General guidelines for protecting network:–Allow only network administrators to create or modify NOS and application system files–Monitor network for unauthorized access or changes–Record authorized system changes in a change management system–Install redundant components–Perform regular health checksNetwork+ Guide to Networks, 4e 5What Are Integrity and Availability? (continued)•General guidelines for protecting network (continued):–Check system performance, error logs, and system log book regularly–Keep backups, boot disks, and emergency repair disks current and available–Implement and enforce security and disaster recovery policiesNetwork+ Guide to Networks, 4e 6Viruses•Program that replicates itself with intent to infect more computers–Through network connections or exchange of external storage devices–Typically copied to storage device without user’s knowledge•Trojan horse: program that disguises itself as something useful but actually harms system–Not considered a virusNetwork+ Guide to Networks, 4e 7Types of Viruses•Boot sector viruses: located in boot sector of computer’s hard disk–When computer boots up, virus runs in place of computer’s normal system files–Removal first requires rebooting from uninfected, write-protected disk with system files on it•Macro viruses: take form of macro that may be executed as user works with a program–Quick to emerge and spread–Symptoms vary widelyNetwork+ Guide to Networks, 4e 8Types of Viruses (continued)•File-infected viruses: attach to executable files–When infected executable file runs, virus copies itself to memory–Can have devastating consequences–Symptoms may include damaged program files, inexplicable file size increases, changed icons for programs, strange messages, inability to run a program•Worms: programs that run independently and travel between computers and across networks–Not technically viruses–Can transport and hide virusesNetwork+ Guide to Networks, 4e 9Types of Viruses (continued)•Trojan horse: program that claims to do something useful but instead harms system•Network viruses: propagated via network protocols, commands, messaging programs, and data links•Bots: program that runs automatically, without requiring a person to start or stop it–Many bots spread through Internet Relay Chat (IRC)–Used to damage/destroy data or system files, issue objectionable content, further propagate virusNetwork+ Guide to Networks, 4e 10Virus Characteristics•Encryption: encrypted virus may thwart antivirus program’s attempts to detect it•Stealth: stealth viruses disguise themselves as legitimate programs or replace part of legitimate program’s code with destructive code•Polymorphism: polymorphic viruses change characteristics every time transferred •Time-dependence: time-dependent viruses programmed to activate on particular dateNetwork+ Guide to Networks, 4e 11Virus Protection: Antivirus Software•Antivirus software should at least:–Detect viruses through signature scanning–Detect viruses through integrity checking–Detect viruses by monitoring unexpected file changes or virus-like behaviors–Receive regular updates and modifications from a centralized network console–Consistently report only valid viruses•Heuristic scanning techniques attempt to identify viruses by discovering “virus-like” behavior (may give “false positives”)Network+ Guide to Networks, 4e 12Antivirus Policies•Provide rules for using antivirus software and policies for installing programs, sharing files, and using floppy disks•Suggestions for antivirus policy guidelines:–Every computer in organization equipped with virus detection and cleaning software –Users should not be allowed to alter or disable antivirus software–Users should know what to do in case virus detectedNetwork+ Guide to Networks, 4e 13Antivirus Policies (continued)•Suggestions for antivirus policy guidelines (continued):–Antivirus team should be appointed to focus on maintaining antivirus measures–Users should be prohibited from installing any unauthorized software on