13. Network Problems and Solutions

1. 13. Network Problems and Solutions Networking and Telecommunications

2. Cables • Problems - crosstalk, emi, rfi, close to interference • Solution - twisted pair (higher grade), shielded wire, fiber optic, run cables carefully, don’t violate rules (too long cable runs), use proper standard cables, keep way from sources of interference (flourecent lights) • Problems - improper ends, loose connections • Solution - crimping tool, wire testers

3. Server/Client • Problems - hardware failures (hard drives, cpu board, nic, etc) • Solutions - UPS, disk mirroring, raid, redundancy, spare parts, maintenance contracts • Problems - software failures (NOS) • Solutions- patches, new versions, backups (tape)

4. Operation Room • Problems - heat/humidity, power, fire, physical security • Solutions - air conditioner/humidifier, UPS, sprinklers, locks, swipe cards, motion detectors

6. Networking • Problems - high traffic volumes, slowness • Solutions - use bridges, switches, or a higher speed lan technology (like 10baseT to 100baseT) • Problems - ports on hub/switches not talking to NICs • Solutions - check setting on port (10 vs.100, full vs. half duplex, auto-negotiate) • Problems – collisions • Solutions – Non-contention Network Architecture (token ring, FDDI) or Full Duplex Fast Ethernet, use switches

7. Lan Monitoring Tools • Watch traffic and packets • History, snmp • Watch hubs, switches, routers • Watch and Repair • Reset, UP/Down Port

8. Network Security

9. Typical Problems • Viruses (I love You/Melissa/Sircam virus) - floppy/email attachments, human intervention to spread. Anti-Virus software (detect and clean)...keep up-to-date. • Worms (sendmail, code red, nimda, Nachia, SoBig) - automatic spreading using vunerabilities in the operating system • Trojan horses (mimic other programs...like login screens)

10. Typical Problems (cont.) • DOS attacks (denial of service) - yahoo/microsoft problems. DDOS (distributed DOS) • ip spoofing - fake source ip address to appear local (block via router and ACL) • Gain root/adminstrator access • Packet sniffing • SPAM (unwanted junk email)- more of an annoyance • Spyware-pop-ups, redirected webpages

11. What Hackers like to do? • Deface, take over systems, backdoors, root kits, launching pad to attack others, keep hidden • “Networks are a virtual petri dish for breeding computer viruses"

12. How to combat? • Boot from server, disable floppy (diskless workstations), boot rom chips • Don’t open email attachments! • User permissions/passwords on server, ACL (access control lists), file/directory permissions • Router ACL- control access, filter packets, limit bandwidth (dorms) • Share only what data is needed from server to client • Frequent backups, data encryption

13. How to combat? (cont.) • Authorization/authentication • Audit trails/logs • Call back systems via modems, one time password cards (enigma or secure-id) • Fiber optic cables • Firewalls • IDS (Intrusion detection systems), sends alerts (logs, email, pager, etc.) • Physical locks, swipe cards, motion detectors, login/passwords

14. How to combat? (cont.) • Outside intruders (hackers), and internal concerns • Security patches, OS up to date • bulletins, mailings lists, newsgroups • Virus scanning software (up to date) • Be careful of wireless lans and other shared media (hubs) • Use of VPN • Anti-Spam Software (spam assassin) • Ethics • Fight Spyware using software like Adaware, or Spybot

15. "Multiple Lines of Defense !!!" "Multiple Lines of Defense !!!" "Multiple Lines of Defense !!!" "Multiple Lines of Defense !!!" "Multiple Lines of Defense !!!" "Multiple Lines of Defense !!!" "Multiple Lines of Defense !!!" "Multiple Lines of Defense !!!" "Multiple Lines of Defense !!!" "Multiple Lines of Defense !!!"

16. Multiple Lines of Defense !!

17. THE END!!