Proxy servers and firewalls act as intermediaries between internal networks and external networks like the internet. Proxy servers can cache content to improve performance, control bandwidth usage, and filter requests. Firewalls protect internal networks from external threats by analyzing and filtering incoming and outgoing packets. Popular proxy software includes Squid, ISA Server, and WinRoute, while popular firewall software includes ZoneAlarm, Norton Internet Security, and Cisco PIX.

1. Proxy Servers & Firewalls

2. What is proxy ? Main purpose of using proxies How a proxy works ? Proxy types Popular hardware & software proxies What is firewall ? Main purpose of using firewalls How a firewall works ? Firewall types Popular hardware & software firewalls Objectives

3. What is proxy ? Proxy Proxy is hardware / software Indirect access to other networks e.g INTERNET. all computers on the local network have to go through it before accessing information on the Internet. Organization , universities , companies use proxy systems Proxy act as gateway Proxy act as Cache Server/Firewall Proxy share a connection to others LAN INTERNET

4. Main purpose of using proxies Improve Performance Act as Cache server Bandwidth control Filter Requests Prevent access to some web sites!!! Prevent access to some protocols Time division Surfing Anonymously Browsing the WWW without any identification!!!

5. Improve Performance Caching Reduce latency Reduce Network Traffic Caching can greatly speed up Internet access. If one or more Internet sites are frequently requested, they are kept in the proxy's cache, so that when a user requests them, they are delivered directly from the proxy's cache instead of from the original Internet site. Caches diminish the need for network bandwidth, typically by 35% or more, by reducing the traffic from browsers to content servers. Bandwidth control Policy-based Bandwidth Limits Deny by content type INTERNET 64 Kbps 128 Kbps 512 Kbps 1 Mbps

6. Filter Requests Prevent access to some web sites!!! Categories web sites Adult/Sexually Explicit Advertisements & Pop-Ups Chat Gambling Games Hacking Peer-to-Peer …… Check by content type .Exe / .Com .Mid / .MP3 / .Wav .Avi / .Mpeg / .Rm

7. What do you need for proxy installation? Proxy Software Ms ISA Server , Squid , WinRoute , … Server At least 2 network cards DIRECT INTERNET connection (Public IP Address) Switch/Hub (elective) Private IP Address 10.0.0.1/8 – 172.16.0.1/16 – 192.168.0.1/24

8. How a proxy works ? See the next Demo

9. IP : 172.16.0.2 Gw : 172.16.0.1 IP : 172.16.0.1 IP : 217.219.66.2 Gw : 217.219.66.1 LAN INTERNET Proxy Server Source IP 172.16.0.2 www.yahoo.com Dest IP 209.191.93.52

10. IP : 172.16.0.2 Gw : 172.16.0.1 IP : 217.219.66.2 Gw : 217.219.66.1 IP : 172.16.0.1 Change Source IP Address LAN INTERNET Proxy Server Source IP 217.219.66.2 www.yahoo.com Dest IP 209.191.93.52 Source IP 172.16.0.2 www.yahoo.com Dest IP 209.191.93.52

11. IP : 217.219.66.2 Gw : 217.219.66.1 IP : 172.16.0.1 Change Source IP Address & Destination IP Address IP : 172.16.0.2 Gw : 172.16.0.1 LAN INTERNET Proxy Server Source IP 209.191.93.52 Dest IP 217.219.66.2

12. IP : 217.219.66.2 Gw : 217.219.66.1 IP : 172.16.0.1 Change Dest. IP Address IP : 172.16.0.2 Gw : 172.16.0.1 LAN INTERNET Proxy Server Source IP 209.191.93.52 Dest IP 217.219.66.2 Source IP 209.191.93.52 Dest IP 172.16.0.2

13. IP : 172.16.0.2 Gw : 172.16.0.1 IP : 217.219.66.2 Gw : 217.219.66.1 IP : 172.16.0.1 LAN INTERNET Proxy Server Source IP 209.191.93.52 Dest IP 172.16.0.2

14. Proxy types Web proxies SSL proxies Transparent proxies Open proxies Proxy setting in IE

15. Popular hardware & software proxies Software Proxy Hardware Proxy Ms. ISA Server Cisco PIX Squid Blue Coat Kerio WinRoute Cyberoam 1st Up Net Server Alacer CCProxy CProxy Windows ICS WinGate

16. What is firewall ? Firewall Firewall is hardware / software protects the resources of a private network from users from other networks Organization , universities , companies use firewall systems Firewall can act as gateway Firewall can act as proxy Firewall filter Incoming & Outgoing information LAN INTERNET

17. Main purpose of using firewalls Packet filtering Analyzing packets Proxy service Provide access to other networks e.g INTERNET   LAN INTERNET

18. How a firewall works ? The FIREWALL can now: Log the attempt Alert the admin Harden the firewall Or reset a TCP/IP connection Sniffing Mode 1) An attacker tries to compromise a service on the protected network. 2) The Firewall identifies the attempt . LOG Alert  Reset Harden

19. What firewall protects us from Remote login Application backdoors Operating system bugs Denial of service E-mail bombs Viruses SPAMs Trojans ICMP bombing FTP brute force Phishing … .

20. Popular hardware & software firewalls Software Firewall Hardware Firewall Ms. ISA Server Cisco PIX Norton Internet Security Blue Coat Mcafee Internet Security Cyberoam ZoneAlarm Check Point Kerio NetScreen BlackICE D-link SECURESPOT Outpost WatchGuard

21. Thank You References : www.cisco.com www.isaserver.org www.wikipedia.com www.cert.org www.isc.sans.org www.zonelabs.com www.symantec.com www.mshdiau.ac.ir