1. Section 7: TCP/IP Fundamentals CSIS 479R Fall 1999 “Network +” George D. Hickman, CNI, CNE

2. Objectives Describe the IP address structure Identify network classes Obtain a registered IP address Register a Domain name Assign addresses to hosts Describe how host names, host tables, and DNS work

3. Objectives (con’t) Describe Windows Internet Name Services (WINS) Describe how ports are used Explain the purpose of subnets Define a subnet mask Describe how subnet masks are used Assign subnet addresses

4. IP Address Structure 4 bytes or 32 bits called a “dotted quad” Comprised of a network ID and a host ID Host is a server, workstation, or other node Routers on Internet route messages to the Network ID portion Once message gets to correct network, it is delivered based on the node address

5. IP addresses 172.16.4.2 –Base 10 numbers 10101100.00010000.00000100.00000010 –Binary number system Same address

6. Network Classes Class A –Network number 1-127 Class B –Network number 128-191 Class C –Network number 192-223 Class D –Network number 224-239 Class E –Network number 240-255

7. Network Classes Class A Network number 1-127 –0xxxxxxx.x.x.x 126 networks, 16,777,216 hosts Class B Network number 128-191 –10xxxxxx.x.x.x 16,384 networks, 65,534 hosts Class C Network number 192-223 –110xxxxx.x.x.x 2,097,152 networks, 255 hosts Class D Network number 224-239 –1110xxxx.x.x.x Multicast packets Use is router communications Class E Network number 240-255 –11110xxx.x.x.x Experimental use and future addressing modes address 255.255.255.255 is to all hosts on this network

8. Special IP Addresses network 0.0.0.0 –The default route. Used in routing tables network 127.0.0.0 –Loopback. 127.0.0.1 is local host All network bits set to 0 –A host on “this” network. 0.0.0.34 is host 34 on this class A network

9. Special IP Addresses (con’t) All host bits set to 0 –Refers to the network. 145.67.0.0 refers to network 145.67.x.x Used within routing tables Network or node address with all bits set to 1 –Refers to all networks or all hosts 255.255.255.255 –Broadcast to all hosts on this network only

10. Obtain a Registered IP Address InterNIC or Network Solutions ARIN American Registry for Internet Numbers RIPE Reseaux IP Europeans APNIC Asia Pacific Network Information Center Addresses are given to major ISPs, who assign numbers to their customers

11. Register a Domain Name My business name is “Technology Trainers” I “own” www.technologytrainers.comwww.technologytrainers.com Registered the name, pay InterNIC a fee for a “business card” at that location to hold the name. Renew every 2 years

12. Domains.COM –Commercial entities –www.novell.com.EDU –Educational. Now mostly 4 year colleges and Universities –www.uvsc.edu.GOV –Government, non military, non educational –www.whitehouse.gov.INT –Organizations established by International treaties ??

13. Domains (con’t).MIL –US Military –www.army.mil.NET –Network providers –www.pacbell.net.ORG –Non-profit and other organizations that don’t fit anywhere else –www.lds.org

14. Domains (con’t) Country codes Australia –AU Brazil –BR Canada –CA Dominican Republic –DO

15. Country Domains Egypt –EG France –FR Germany –DE Hong Kong –HK

16. Country Domains (con’t) India –IN Japan –JP Kuwait –KW Malaysia –MY

17. Country Domains (con’t) New Zealand –NZ Oman –OM Portugal –PT Great Britain –UK

18. Private Network Addresses Filtered out by Internet routers (RFC 1918) Class A 10.0.0.0 to 10.255.255.255 Class B 172.16.0.0 to 172.31.255.255 Class C 192.168.0.0 to 192.168.255.255 If you are connected to the Internet, you must use registered addresses!

19. Host Tables Internet-Address official-host-name aliases 132.132.87.176 argo 132.132.12.45 pacific pa 132.132.19.42 sales.vax 127.0.0.1 loopback #loopback DNS server resolves names by referring to table

20. Subnets A way of overcoming the limitations of a single or limited number of networks, by making sub- networks. –To extend the network (overcome physical limits) –To reduce congestion –To reduce CPU use (less broadcasts) –To isolate network problems –To improve security –To use multiple media

21. Subnet mask “Borrow” bits from the host (or node) address to create sub-networks All IP Addresses MUST have a subnet mask, even if it is the default Mask is a dotted quad number, logically ANDed with the IP address to identify which bits are network and which are host or node address Any bit that is part of the network address has a “1” value in the subnet mask

22. Default Masks Default masks do no additional subnetting Class A 11111111.00000000.00000000.00000000 255.0.0.0 or FF.0.0.0 Class B 11111111.11111111.00000000.00000000 255.255.0.0 or FF.FF.0.0 Class C 11111111.11111111.11111111.00000000 255.255.255.0 or FF.FF.FF.0

23. # of Subnet bits Possible subnet addresses (Binary) Byte in corresponding subnet mask Possible subnet addresses 1 1 000 0000 0 000 0000 1 000 0000128* 0* 2 11 00 0000 10 00 0000 01 00 0000 00 00 0000 11 00 0000192* 128 64 0* 3 111 0 0000 110 0 0000 101 0 0000 100 0 0000 011 0 0000 010 0 0000 001 0 0000 000 0 0000 111 0 0000224* 192 160 128 96 64 32 0*

24. Subnet addresses from Mask Subnets of all [0]s or all [1]s are reserved in TCP/IP networks. NetWare (and most other industry implementations) will allow their use, but be sure all your routers and other NOSs will support it first ! That means the number of available subnets is

25. Classful and Classless Hierarchies Classful Hierarchy –Uses default masks, no subnets Classless Subnet Hierarchy –Network address, Subnet address, Host address Internet routers route by the default mask Routers within the network apply the subnet mask

26. Partial bytes as subnets Book Example page 7-40 Class C address, subnet mask of 255.255.255.224 5 bits left for host

27. Subnetted Class C Masked bits BinaryDecimalSubnetsHosts 11000 00001282 21100 0000192464 31110 0000224832 41111 000024016 51111 1000248328 61111 1100252644 71111 11102541282

28. Assign Subnet Addresses Each address must be unique Network and subnet numbers must be the same for all devices on the same network The Host portion of the address cannot be all [1]s or [0]s Plan for growth Don’t use reserved addresses

29. Plan for Growth How many subnets do I need today? How many subnets will be needed in the future? What is the maximum number of hosts on the largest segment? How many hosts will there be on the largest segment in the future?

30. Assigning Addresses Assign subnets from the left most bit Assign hosts from the right most bit This leaves a buffer zone between hosts and subnets, for future use See page 7-46 Subnet Calculator www.net3group.com/download.html-ssi

31. Steps for creating subnets Determine the number of subnets you need Determine your subnet mask and subnet addresses Assign IP addresses to each host on a subnet Formulas (page 7-49) –n=number of masked address bits –m=number of unmasked address bits

32. Determine the number of subnets you need Keep in mind growth Book example 6 subnets are needed now, but they reserved the entire third byte for future needs This gives growth possibility of 254 subnets

33. Determine Subnet Mask and Subnet Addresses Determine the number of available subnet address values and the number of available host address values per subnet Class B address, 3 masked bits (255.255.224.0) –

34. Calculate the subnet address values Calculate the Delta (the decimal value of the rightmost mask bit) Add Delta to the original network address to obtain the first subnet address value Add Delta to the previous value to determine the next subnet value Continue until the value is >254 Example on page 7-51/52

35. Assign IP Addresses to each host Book example page 7-53 All addresses must be 132.132.x.y X must be [100x xxxx] –Therefore x is between 128 [1000 0000] and 159 [1001 1111] Y can be 0 [0000 0000] – 255 [1111 1111] Exceptions: –132.132.128.0 and 132.132.159.255 are invalid –Invalid because all node bits are set to either 0 or 1

36. Exercises Do exercises 7-3 and up beginning on page 7-54