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Network Technology Foundations © 2004 ProsoftTraining All Rights Reserved Lesson 5: Network Security and IT Career Opportunities Objectives Define security Identify various kinds of network attacks Describe computer viruses Describe authentication principles Explain the three major types of encryption Describe network security protocols and technologies Describe firewalls, security zones and common firewall topologies Describe security audit principles Describe the function of a UPS Review career opportunities in the IT industry Describe the importance of successfully explaining technical issues to non-technical audiences Defining Security Security — a set of procedures designed to protect transmitted and stored information, as well as network resources Security administrators must determine which people can take appropriate actions on specific items at the appropriate time Overview of Network Attack Types Spoofing Man in the middle DOS Distributed DDOS Brute force Dictionary Back door Buffer overflow Trojan horse Social engineering • To avoid attacks: • Install stable updates • Use encryption • Be suspicious of information requests • Remain informed Viruses and Worms Virus — code that causes damage to systems Virus types • Macro/script • File infecting • Boot sector • Stealth • Polymorphic • Retro Worm — similar to virus but automatically replicates Defeating Attacks OSI/RM security services • Authentication • Access control • Data confidentiality • Data integrity • Non-repudiation Updates Authentication Three authentication methods • What you know • What you have • Who you are Passwords • Strong passwords • Age passwords appropriately Account lockout — disables accounts after a given number of invalid passwords have been entered Account reset — enables you to choose whether accounts reset automatically after a given interval Encryption The primary means to ensure privacy across the enterprise Symmetric-key encryption • One key to encrypt and decrypt • All parties must know and trust one another Symmetric algorithms: • DES • Triple DES • AES Encryption (cont’d) Asymmetric-key encryption • Uses a key pair (one public, one private) • Used to create a digital signature Asymmetric algorithms • RSA • DSA Encryption (cont’d) Hash encryption • Uses a hash table that contains a hash function • Used for information that will not be decrypted or read Hash algorithms • MD2, MD4 and MD5 • SHA Encryption (cont’d) PGP — uses a combination of the three encryption types For example: • Use symmetric-key encryption to scramble the original message you want to send • Use asymmetric-key encryption to encrypt only the symmetric key you just used • Use hash encryption to "sign" the message and ensure that no one can tamper with it Virtual Private Network (VPN) A technique that allows secure communication across long distances, usually for a company extranet In a VPN, the Internet is often the corporate network backbone Appropriate for any organization requiring secure external access to internal resources All VPNs are tunneling protocols — encryption occurs at the source and decryption occurs at the destination Virtual Private Network (VPN) (cont’d) VPN protocols • PPTP — works only with IP protocols • L2TP — works with non-IP protocols • IPsec — more flexible than PPTP or L2TP because you can specify different authentication methods Remote Access Server (RAS) Requires the use of dial-up modems to dial up, connect and log on to RAS Offers security through a callback feature: • A user logs on to RAS • The user is disconnected • RAS calls the user back to ensure the call was made from an authorized computer Digital Certificates Provide authoritative identification Verify the sender's identity Use the X.509 standard Are used for non-repudiation Contain digital signatures • CA Public Key Infrastructure (PKI) PKI CA servers: • Are repositories for managing digital certificates • Enable the secure creation and management of digital certificates • Provide the ability to revoke an invalid key If you need a certificate for a server, use PKI Firewall A secure computer system placed between a trusted network and an untrusted one, such as the Internet • The most common location for a firewall is between a corporate LAN and the Internet Allows users from a protected network to access a public network while simultaneously making the protected company's products and services available to the public Internal and Personal Firewalls Internal firewall — resides inside your company's internal network • Internal firewalls can: Protect sensitive systems Isolate networks that still need Internet connectivity but that use software that may cause problems with other company resources Personal firewall — offers protection for an individual system Packet Filtering Packet filter — inspects each packet for predefined content Packet filters filter data based on the following fields in the packet: • Source IP address • Destination IP address • TCP/UDP source port • TCP/UDP destination port Proxy Server Replaces the network IP address with a single IP address Provide the following services: • Hiding of network resources • Logging • Caching Proxies come in two basic forms: • Circuit-level gateways • Application-level gateways Proxy Gateways Circuit-level gateway — acts as a proxy between the Internet and your internal systems Application-level gateway — same as a circuitlevel gateway but at the application level Most firewalls are combinations of packet filtering, circuit-level gateways and applicationlevel gateways Network Address Translation (NAT) The practice of hiding internal IP addresses from the external network Three ways to provide NAT: • Configure masquerading on a packetfiltering firewall • Configure a circuit-level gateway • Use a proxy server to conduct requests on behalf of internal hosts Accessing Internet Services If Internet access is required and a network is located behind a proxy server or firewall, you may have problems accessing Internet services that use ports other than common ports To avoid these problems: • Make sure the network has access to all Internet-related protocols used by the company • Make sure that the IP addresses assigned to the computers in your network have permission to access the Internet Troubleshooting Access Through Firewalls Firewalls can cause a bottleneck Firewalls may not allow homebased account access to the corporate e-mail server To troubleshoot firewall problems: • Verify that you are using the correct IP address and subnet mask • Check your default gateway and verify that the computer can communicate with systems on the same subnet Security Zones DMZ — a mini-network that resides between a company's internal network and the external network Intranet — a security zone available only to authorized organization employees Extranet — a private network that allows selected access to outsiders only after they provide authentication information VLAN — a logical grouping of hosts, generally not implemented by a firewall Firewall Topologies Common firewall implementations: • Packet filter • Dual-homed bastion host • Triple-homed bastion host • Screened subnet (back-to-back firewalls) Bastion host — a computer that houses various firewall components and services and is connected to a public network Packet Filter Topology Dual-Homed Bastion Host Triple-Homed Bastion Host Screened Subnet Security Audit Review of the state of the network Auditing process: • Conduct a status quo analysis • Conduct a risk analysis • Make recommendations concerning what was found Uninterruptible Power Supply (UPS) Device that allows a computer to keep running temporarily when the primary power source is lost Can be configured to: • Shut down entire systems automatically • Shut down only certain components automatically • Place components into minimal power use mode until the system is shut down manually IT Industry Career Opportunities Web site designer Web application developer Web architect Web site analyst Web site manager Database administrator Server administrator Network engineer Security manager Security analyst/consultant PC repair technician Help desk technician Conducting Job Searches Participating in on-campus interviews Searching through want ads Visiting employment agencies/employment placement services Attending job/career fairs Volunteering Seeking part-time work Networking (socially) Working with an executive search firm Mailing cover letters and résumés to companies Applying in person Entering résumés electronically or posting them to the Web Using the Internet to Conduct Job Searches Use Usenet job newsgroups and search engines, such as: • groups.google.com • hotjobs.yahoo.com • careers.excite.com • www.monster.com Enter keywords to narrow your search to specific job types, and retrieve available job listings that relate to your career goals Creating a Résumé Formatting a résumé: • Create using a word-processing program • Use formatting to increase visual appeal • Recipient needs same word-processing program to be able to read résumés Text format résumés: • Contain little formatting • Intended for keyword-searchable résumé databases and applicant tracking systems RTF résumés: • Incorporate basic formatting techniques • Can be read by many different programs on Creating a Résumé (cont’d) PDF résumés: • Compatible across all computer platforms • Not vulnerable to viruses • Need PDF software HTML résumés: • Posted as Web pages • Retain the formatting characteristics of a word-processing file Education and IT Careers University degrees are available in: • Computer science • Computer engineering • Management information systems Employers are also looking for: • Interpersonal skills • Business skills • Project management skills Education and IT Careers (cont’d) Importance of continuing education Obtain certifications in: • A+ • CIW • Network+ • Security+ Certification Technical Concepts and Training Communicating technical issues to end users Justifying IT-related expenses to management Understanding problems and concerns of end users Providing understandable solutions Remembering the ROI affect of IT decisions Presenting technical data clearly so that managers understand the information and can make informed decisions