1. CISCO NETWORKING ACADEMY Chabot College ELEC 99.05 Internet Security Introduction

2. CISCO NETWORKING ACADEMY Internet Security TCP/IP and the internet were designed by professionals with a common culture and cooperative goals. Today they are used by a wide range of persons with varying and sometimes malicious goals. The technology of TCP/IP does not assure user security. There are many points at which TCP/IP security can be compromised.

3. CISCO NETWORKING ACADEMY Internet Security Security intrusions over the internet are common. The following slide shows 48 hours of intrusion attempts against a DSL-connected PC… –Note that the probes come from all over the world, including Romania. –Most of these attempts are from “script kiddies” running a program on a PC to grind through a range of IP addresses.

4. CISCO NETWORKING ACADEMY Probes Against DSL-Connected Machine

5. CISCO NETWORKING ACADEMY Security Strategies Use a NAT router to connect to DSL or cable modem. Use a software firewall for dial-up, DSL or cable modem. –(e.g. Zone Alarm, from www.zonelabs.com - free)www.zonelabs.com Read Steve Gibson’s excellent Shields-UP site and follow his configuration advice. (free)

6. CISCO NETWORKING ACADEMY Shields UP Key ideas from Shields UP: –As delivered, Windows is not secure when connected to the internet. –The key problems can be fixed by a free reconfiguration. –Free software firewalls are recommended.

7. CISCO NETWORKING ACADEMY Shields UP Here’s how windows protocol bindings are delivered: Layer 1&2 Layer 3 Higher Layers

8. CISCO NETWORKING ACADEMY Shields UP Binding these Microsoft network services to TCP/IP creates security vulnerabilities! Problem Bindings

9. CISCO NETWORKING ACADEMY Shields UP Here are the bindings needed for access to the internet:

10. CISCO NETWORKING ACADEMY Shields UP The excellent Shields Up site tells you how to do it! Bonus Credit Assignment - fix your home PC! http://www.grc.com