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Network Administrators: Your Networking Support Team

"Need assistance with computer networks? From network basics to communication programs, encryption, digital signatures, and password security, our network administrators are here to help and provide guidance on various network-related topics. Submit a ticket on our support website to get started!"

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Network Administrators: Your Networking Support Team

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  1. Computer networks Network administrators are here to help you! Open a ticket on http://support.unibz.it Computer networks

  2. Computer networks • What is a network • Computers • External connection • Terminals • Printers • Stand-alone hard disks • VoIP telephones • Server-client architecture Computer networks

  3. Transfer speed • Network areas • Local Area Network (LAN, Intranet) • Wide Area Network (WAN, Internet) • Virtual Private Network (VPN) • Speed in “bits per second” (bps) • Ethernet 10 Mbps • Fast Ethernet 100 Mbps • Giga Ethernet 1 Gbps • Wireless 30-300 Mbps Computer networks

  4. Communication programs • Web browser • Chrome (55% of the market) • Mozilla Firefox (25% of the market) • Internet Explorer (10% of the market) • Safari • Mail reader • Outlook, Mozilla Thunderbird, Windows Live Mail • Webmail and Microsoft Outlook Web App http://webmail.unibz.it • Voice over IP • Costs • WhatsApp Computer networks

  5. Posta Elettronica Certificata – PEC • Standard email • No guarantee of sender’s e-mail address identity • No guarantee of sender’s identity • No guarantee that content has not been altered • No sent proof • No dispatched proof • No read proof • PEC to PEC: like a raccomandata con ricevuta di ritorno • Sent proof • Dispatched proof • (in practice also) sender’s address identity and unaltered content Computer networks

  6. Posta Elettronica Certificata – PEC • PEC to standard email: like a raccomandata semplice • Sent proof • Standard email to PEC: like a normal letter • Sent and dispatched proves are legal proves • Every citizen may have a free PEC address to communicate with public administration Computer networks

  7. Search engines • Crawler technique (8 billions web pages!) • Google scoring system • Search tricks: • Use many keywords • Quotations • Advanced search • Search for images Computer networks

  8. Slow connections Computer networks

  9. Broadband connections Computer networks

  10. Broadband connections • ADSL Congestion • “minimum band guaranteed” contract • Digital divide • 5,400,000 Italians not covered by broadband • WiMax • 10 Kilometers range • “line of sight” problem Computer networks

  11. Law 196/2003 on privacy • Data are divided into: • personal data • sensitive data • race and ethnicity, • religious / philosophical / political opinions, • belonging to religious / philosophical / political / workers organization • sensitive data about health and sex • justice data (handled as sensitive data) • genetic data (need extremely particular procedures) Computer networks

  12. Law 196/2003 on privacy • To personal users who do not communicate data only security requirements apply • Requirements • authentication with login + password or alternatives • permission • training or instructions • backup every week all data • security programs updated every 12 months (6 if sensitive) • sensitive data must be encrypted or unidentifiable Computer networks

  13. Encryption • Scrambling technique to make text unreadable • Public key for encrypting • Private key for decrypting • 128 bits to be sure Computer networks

  14. decrypt decrypt decrypt encrypt encrypt B B G#4hg! G#4hg! message 1 Trb:-ò°§ message 1 message 1 Encryption for information exchange A C C encrypt encrypt decrypt decrypt message 2 f@çd*s f@çd*s Dr4^\|ò9 message 2 message 2 encrypt encrypt decrypt D D message 3 %$&/òL message 3 message 3 È^£(iw, È^£(iw, Computer networks

  15. secret data secretdata secretdata %£)(“84jhgds?ì A A A encrypt encrypt D(£ò§*+]dH D(£ò§*+]dH decrypt decrypt Encryption for data storage Computer networks

  16. Digital signature • Law 82/2005 • Private key for encrypting • Public key for decrypting • Keys given by certification authorities • Combination with PEC • Keys expiration • Temporal mark Computer networks

  17. B B 2?=zx:-ki document decrypt decrypt Digital signature A document falsedocument Y&”:ò[fgj?’^d G#4$h&à?-2y encrypt encrypt C C decrypt decrypt 2?=zx:-ki document decrypt decrypt D D 2?=zx:-ki document Computer networks

  18. Comparison with handwritten signature Computer networks

  19. Electronic vs digital signature • Electronic signature • automatic signature through username and password • Qualified electronic signature • and a certification authority guarantees it • Digital signature • and uses encryption Computer networks

  20. Passwords Computer networks

  21. Passwords • What can be done with your password? • Steal personal data • Steal other people’s data • Steal money • Delete and modify data • Steal identity • Start illegal activities Computer networks

  22. Passwords • Most people have the following passwords: • A standard computer can try 4 billion passwords per second Computer networks

  23. Passwords • Law 196/2003 • Avoid personal data in the password • Change password every 6 months (3 if sensitive data) • Minimum 8 characters • Better also: • Mix letters, strange characters and numbers • Do not use words • Use different passwords for different purposes • Beware of passwords stored in programs • Test your password robustness on https://howsecureismypassword.net • What to do in case of employee’s absence Computer networks

  24. Alternatives to password • Law 196/2003 allows biometric identification methods • fingerprints • hand palm • retina scanning • voice identification Computer networks

  25. Extra security • Adding physical methods to standard password • smartcard • token key • OTP with display • OTP USB • phone SMS • phone call Computer networks

  26. Viruses • What does a virus do? • Infect • Survive • Duplicate • Damage • Virus infection symptoms • computer is slow to start • unwanted and annoying pop-ups • many system errors Computer networks

  27. Viruses • User’s responsible behaviors • downloaded files and email attachments • CD, DVD, USB pendrives • strange websites • updated programs • updated antivirus • Anti-viruses • Checking the whole hard disk • Checking suspect files • Always running Computer networks

  28. Types of viruses • Trojan horse • looks like a good program • Key logger • records your keyboard activity (to get passwords) • Back door • opens a port on your computer (to let external users in) • Adware • displays advertisement • Spyware • spies your activity (to get passwords or for spam targeting) Computer networks

  29. Spam • “unsolicited” “unwanted” “bulk” email • Advertisement: gambling, pornographic websites, medicines, risky investments, software… • Chain letters • Frauds • Phishing • Sender is always counterfeited • Do not click on links! Do not answer!!! • Where do they get my email address? • Antispam and blacklists Computer networks

  30. Phishing Computer networks

  31. Phishing Computer networks

  32. Phishing example • 2,000,000 emails sent • 5% arrive to existing users: 100,000 • 5% of users read the email: 5,000 • 2% of readers believe in the email: 100 • $1,200 from each user •  Gain: $120,000 • In 2005 Mr. David Levi gained $360,000 from 160 people using Phishing on eBay website Computer networks

  33. Safe navigating • Navigation security • Phishing • Viruses • Download  Save  Antivirus  Open • Avoid visiting and downloading from untrustworthy websites • Keep Explorer and Windows up-to-date • Intercept your data • Secure connection SSL: httpS Computer networks

  34. Attacks from outside • Denial of Service • zombie computers • Firewall • which internal program • which external address • what amount of traffic • which kind of data • Windows Seven Firewall Computer networks

  35. Backup • Why backup? Source: The Cost of Lost Data. The importance of investing in that “ounce of prevention” by David M. Smith Computer networks

  36. Backup • Law 196/2003 • backup every week • What to backup? • Your data files • emails, contacts, calendar • Program configuration files • Difficult-to-find stuff • Where to backup? • another hard disk • online backup systems: Dropbox, GoogleDrive, Box, Amazon • RAID techniques Computer networks

  37. RAID – Redundant Array of Independent Disks • JBOD – Just a Bunch Of Disks • 2 disks • RAID 0 • 2 disks, fast • RAID 1 • 2 disks but space as for 1, safe vs crash, 24h service • Most common solution • RAID 10 • 4 disks but space as for 2, fast, safe vs crash , 24h service • None of these techniques is safe versus viruses or human errors! Computer networks

  38. JBOD Computer networks

  39. RAID 1 Computer networks

  40. RAID 0 Computer networks

  41. RAID 10 Computer networks

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