1. Click to edit Master subtitle style Chapter 6: Introduction to the IP Protocol

2. Chapter 6 Objectives The Following CompTIA Network+ Exam Objectives Are Covered in This Chapter: 5.2 Explain the basics of network theory and concepts TCP/IP suite o ICMP o UDP o TCP 5.9 Compare and contrast the following ports and protocols 80 HTTP 443 HTTPS 137-139 Netbios 110 POP 143 IMAP 25 SMTP 5060/5061 SIP 2427/2727 MGCP 5004/5005 RTP 1720 H.323 TCP o Connection-oriented UDP o Connectionless 2

3. Chapter 6 Objectives (cont.) 5.10 Given a scenario, configure and apply the appropriate ports and protocols 20,21 FTP 161 SNMP 22 SSH 23 Telnet 53 DNS 67,68 DHCP 69 TFTP 445 SMB 3389 RDP 3.0 Network security 3.2 Compare and contrast common network vulnerabilities and threats Vulnerabilities o Unsecure protocols TELNET HTTP SLIP FTP TFTP SNMPv1 and SNMPv2 3

4. Chapter 6 Objectives (cont.) 3.3 Given a scenario, implement network hardening techniques Use secure protocols o SSH o SNMPv3 o TLS/SSL o SFTP o HTTPS 4

5. What is TCP/IP? 5 Because TCP/IP is so central to working with the Internet and intranets, it’s essential for you to understand it in detail. TCP/IP first came on the scene in 1973. Later, in 1978, it was divided into two distinct protocols: TCP and IP. Then, back in 1983, TCP/IP replaced the Network Control Protocol (NCP) and was authorized as the official means of data transport for anything connecting to ARPAnet, the Internet’s ancestor that was created by ARPA, the DoD’s Advanced Research Projects Agency way back in 1957 in reaction to the Soviet’s launching of Sputnik. ARPA was soon re-dubbed DARPA, and it was divided into ARPAnet and MILNET (also in 1983); both were finally dissolved in 1990.

6. TCP/IP History 6 Most of the development work on TCP/IP happened at UC Berkeley in Northern California, where a group of scientists were simultaneously working on the Berkeley version of UNIX, which soon became known as the BSD, or Berkeley Software Distribution series of UNIX versions. Of course, because TCP/IP worked so well, it was packaged into subsequent releases of BSD UNIX and offered to other universities and institutions if they bought the distribution tape. All of this led to the DoD model….

7. DoD Model 7 The DoD model is basically a condensed version of the OSI model—it’s composed of four, instead of seven, layers: –Process/Application layer –Host-to-Host layer –Internet layer –Network Access layer The figure on the next slide shows a comparison of the DoD model and the OSI reference model. As you can see, the two are similar in concept, but each has a different number of layers with different names. However, the DoD and OSI are so similar that the layer names are actually interchangeable.

8. DoD Model 8 OSI Model Process/ Application Host-to-Host Internet Network Access Application Presentation Session Transport Network Data Link Physical

9. TCP/IP Protocol Suite 9 DoD Model Process/ Application Host-to-Host Internet Network Access ICMP Telnet TFTP FTP SMTP LPD NFS SNMP X Window TCPUDP Ethernet Fast Ethernet Gigabit Ethernet Wireless /802.11 ARP RARP IP

10. TCP/IP Protocols (cont) Telnet FTP SFTP TFTP SMTP POP IMAP4 RDP SIP ( VOIP) SNMP SSH 10

11. TCP/IP Protocols HTTP HTTPS NTP SCP NTP SCP LDAP IGMP DNS POP DHCP 11

12. DHCP Client four-step process 12 Client Broadcast DHCPDiscover Server Unicast DHCPOffer Client Broadcast DHCPRequest Server Unicast DHCPACK

13. TCP Segment 13 Destination Port (16) Acknowledgement Number (32) Sequence Number (32) Source Port (16) Header Length (4) Window (16)Reserved (6) Code bits (6) Checksum (16)Urgent (16) Options (0 or 32 if any) Data (varies) Bit 0 Bit 15Bit 16Bit 31 24 bytes

14. UDP Segment 14 Destination Port (16) Length (16) Source Port (16) Checksum (16) Data Bit 0 Bit 15Bit 16Bit 31 6 Bytes

15. TCP and UDP 15

16. Port Number Examples 16

17. Chapter 6 Port numbers for TCP and UDP Figure 6.6 Telnet TCP FTP UDP Doom DNS TFTPPOP3 21 23 666 53 69 110 Application layer Transport layer Port numbers News 119

18. IP Header 18 Priority and Type of Service (8) Total length (16) Version (4) Time to Live (8) Fragmented offset (13) Identification (16) Header Length (4) Source IP Address (32) Data (varies if any) Flags (3) Protocol (8) Header Checksum (16) Destination IP address (32) Options (0 or 32 if any) Bit 0 Bit 15Bit 16Bit 31 20 bytes

19. ICMP Example 19 icmp Lab_A Lab_B Host A Host B X e0 e0 on Lab_B is down. Host A is trying to communicate to Host B. What happens?

20. ARP Example 20 IP: 10.1.1.2 = ??? IP: 10.1.1.2 Ethernet: 45:23:79:85:77:34 10.1.1.1 10.1.1.2 I need the Ethernet address of 10.1.1.2 I heard that broadcast. The message is for me. Here is my Ethernet address.

21. RARP Example 21 Ethernet: 45:23:79:85:77:34 IP = ?? Ethernet: 45:23:79:85:77:34 IP: 192.168.10.3 What’s my IP address? I heard that broadcast. Your IP address is 192.168.10.3

22. Data Encapsulation 22 Upper layer data TCP Header Segment IP Header Packet LLC Header Packet MAC Header FCS 0101110101001000010 Application Presentation Session Physical Transport Network Data Link Segment Packet Frame Bits PDU

23. Protocol Data Units 23 Destination MAC Source MAC Ether-FieldPacketFCS Source IP Destination IP Protocol…Segment Source Port Destination Port … Data Segment Packet Frame Bits1011011100011110000

24. Port Numbers at the Transport Layer 24 Source Port Destination Port … 102823… SP DP Defines Virtual Circuit Defines upper layer process or application Host A Host Z

25. Summary 25 Summary Exam Essentials Section Written Labs Review Questions