Computer Networks & FirewallsUniversity IT Security Office - Tom Davis, CISSP University IT Security Officer Office of the Vice President for Information Technology Computer Networks & Firewalls

University IT Security Office - Agenda Networks Firewalls Software Configuration Questions

Computer Networks & FirewallsUniversity IT Security Office - A Word of Warning! Computer geeks love TLA’s And, I’m a computer geek! So, ask questions at anytime…

Computer Networks & FirewallsUniversity IT Security Office - Agenda Networks Firewalls Software Configuration Questions

Computer Networks & FirewallsUniversity IT Security Office - Network Internet Computer AComputer B

Computer Networks & FirewallsUniversity IT Security Office - Networking Terms IP addresses and DNS names –static vs. dynamic IP addresses Port numbers TCP vs. UDP

Computer Networks & FirewallsUniversity IT Security Office - IP Addresses and DNS Names (Static IP Address) Internet peppsi.geology.indiana.edu nlcs.k12.in.us IP = Internet Protocol DNS = Domain Name System

Computer Networks & FirewallsUniversity IT Security Office - IP Addresses and DNS Names (Dynamic IP Address) Internet peppsi.geology.indiana.edu dynamic-69-3.k12.in.us

Computer Networks & FirewallsUniversity IT Security Office - IP Addresses and DNS Names (Dynamic IP Address) Internet peppsi.geology.indiana.edu dynamic-69-3.k12.in.us dynamic-69-7.k12.in.us

Computer Networks & FirewallsUniversity IT Security Office - Port Numbers (nlcs.k12.in.us) Port 80 Port 1568 web scream

Computer Networks & FirewallsUniversity IT Security Office - TCP vs. UDP TCP (Transmission Control Protocol) –delivery is guaranteed (registered letter) –both endpoints are connected UDP (User Datagram Protocol) –delivery is not guaranteed (postcard) –both endpoints are not connected

Computer Networks & FirewallsUniversity IT Security Office - Agenda Networks Firewalls Software Configuration Questions

Computer Networks & FirewallsUniversity IT Security Office - Firewalls Purpose –block network connections, primarily based on: IP address Port number Protocol (TCP or UDP) Masquerading Firewalls –Network Address Translation (NAT)

Computer Networks & FirewallsUniversity IT Security Office - Firewalled Network Internet Firewall Protected Network peppsi.geology.indiana.edu nlcs.k12.in.us

Computer Networks & FirewallsUniversity IT Security Office - Masquerading Firewall Internet firewall.k12.in.us Protected Network peppsi.geology.indiana.edu hidden.k12.in.us

Computer Networks & FirewallsUniversity IT Security Office - Agenda Networks Firewalls Software Configuration Questions

Computer Networks & FirewallsUniversity IT Security Office - Software Configuration IP Address and DNS Name –peppsi.geology.indiana.edu – Ports –1568 (recommended) Protocols: –Your machine sends data to IU via UDP –IU requests data from your machine via TCP

Computer Networks & FirewallsUniversity IT Security Office - Software Issues Dynamic IP addressing IP address blocking Port blocking Protocol blocking (TCP and UDP) Address masquerading

Computer Networks & FirewallsUniversity IT Security Office - Questions?