1. The Internet Just the Facts

2. Protocols TCP/IP are the TRANSPORT protocols of the Internet Services use TCP/IP to connect to other computers on Internet TCP/IP use Network Interfaces (Ethernet, Token Ring, ATM, Frame Relay, DSL, DOCSIS (Cable modem), FDDI, ……

3. TCP/IP Addressing Consists of 4 8-bit Numbers seperated by dots. Must be associated with a subnet mask to be complete. Example: –10.24.244.56 IP Address –255.255.0.0 Subnet Mask –10.24.0.0 Network Address

4. TCP/IP Useability To connect to other networks a router or default gateway must be specified. To convert names (google.com) to numbers (209.85.171.100) a Domain Name Server (DNS) must be specified. TCP/IPv4 is (has) running out of addresses. IPv6 uses 128-bit addresses.

5. IP Default Clases ClassRangeSubnet A 1.0.0.0 – 126.255.255.255255.0.0.0 B 128.0.0 – 191.255.255.255255.255.0.0 C 192.0.0.0 – 223.255.255.255255.255.255.0 D224.0.0.0-239.255.255.255Multicast no Subnet E 240.X.X.X - Experimental

6. Service Protocols ServicePortDescription HTTP80 Web Page Delivery HTTPS443 Secure Web Page Delivery SSL Secure Socket Layer provides Encryption SMTP25 Mail Server to Mail Server (i.e. sending e-mail) POP110 Post Office Protocol (retrieveing E-mail to host)

7. Service Protocols continued ServicePortDescription IMAP143 Internet Message Access Protocol designed to keep messages on server POPs995 Secure POP IMAPs993 Secure IMAP FTP21 File Transfer Protocol (more efficient than HTTP) NNTP119 Network News Transfer Protocol (Discussion Groups)

8. Service Protocols continued ServicePortDescription Telnet23 Connect to a SHELL on a remote computer SSH22 Securely connect to a SHELL on a remote computer PPP Point to Point PPPoE Point to Point over Ethernet PPPoA Point to Point over ATM

9. Internet Naming.COM high-level domain is for Commercial Companies.EDU for colleges and universities.ORG for non-profit organizations.GOV for US Government.MIL for US Military

10. Internet Connections Internet Service Providers (ISP) provide connection Asynchronous Digital Subscriber Line (ADSL) bigger download pipe. Wireless is nice but has security issues Satellite can reach anywhere but has large latencies Internet Connection Sharing (98se, 2K,XP)

11. Connections Continued ISDN BRI: 2 data channels (64k), 1 Control Channel (16k) Web Proxy Server: can improve performance and filter content Proxy set for IE in Connections tab of Internet Tools or in IE E-mail configuration requires Incoming and Outgoing mail servers

12. Browsers For the purposes of A+ the following are legitimate –Internet Explorer

13. Internet Connection Firewall Blocks access to Programs/Ports