1. 4: Addressing Working At A Small-to-Medium Business or ISP

2. Objectives Plan an IP addressing scheme –Subnetting –Classful IPv6 classless routing NAT & PAT

3. Addressing Every device on a network MUST have an IP address! –IPv4 How many bits in an IP address? –32 What’s the maximum amount of bits in an octet? –256 192.168.1.106 –11000000.10101000.00000001.01101010

4. Conversion Practice 1 11100101 to decimal 10001110 to decimal 11111000 to decimal 11111111 to decimal

5. Conversion Practice 2 192 to binary 224 to binary 47 to binary 115 to binary

6. IP Address Review- Class A Range: Default Subnet Mask: Which octets are Network & Host? How many hosts available?

7. Convert A 5 to binary 77 to binary 100 to binary 127 to binary What’s in common with all of them?

8. IP Address Review- Class B Range: Default Subnet Mask: Which octets are Network & Host? How many hosts available?

9. Convert B 128 to binary 142 to binary 191 to binary What’s in common here?

10. IP Address Review- Class C Range: Default Subnet Mask: Which octets are Network & Host? How many hosts available?

11. Convert C 192 to binary 200 to binary 223 to binary What’s common here?

12. Subnet Masks 255.255.255.0 –How many total bits are on? (1’s) 11111111.11111111.11111111.00000000 /24 notation 255.255.0.0 –How many total bits are on? (1’s) 11111111.11111111.00000000.00000000 /16 notation 255.255.255.248 –How many total bits are on? (1’s) 11111111.11111111.11111111.11111000 /29 notation

13. Routers, IP’s & Subnet Masks Router ONLY knows which NETWORKS it is connected to!!! Doesn’t care about individual hosts It ANDs the IP & Subnet Mask Result= DESTINATION NETWORK

14. ANDing

15. Subnet- Split Up the IP Borrow bits to make new networks Plan your network –How many networks? –How many hosts per network?

16. Before we do this… When we borrow, MUST borrow at least 2 bits or leave at least 2 bits –Class C has 1 octet to borrow from –Class B has 2 octets –Class A has 3 octets –2 2 = 4 –2 3 = 8 –2 4 = 16 –2 5 = 32 –2 6 = 64

17. 199.72.101.0

18. 1.199.72.101.0-31 2..32-.63 (.33-.62) 3..64-.95 (.65-.94) 4..96-.127 (.97-.126) 5..128-.159 (.129-.158) 6..160-.191 (.161-.190) 7..192-.223 (.191-.222) 8..224-.255 Total Range #3 –Useable Range #2 Network ID –199.72.101.64 /27 Broadcast Address –199.72.101.95 /27

19. Assign Addresses

20. Router…Action! A packet with a destination IP of 199.72.101.85 255.255.255.224 goes to a router –It ANDs to come up with the NETWORK #

21. Keep It Private Inside hosts have private IP –Only devices that connect directly to Internet have a public IP –Consumer ISR/Routers give out private addresses What’s the Class A private? B? C?

22. Parts of the Network Network Subnetwork Hosts

23. How to Work Backwards 221.17.125.46 /28 –What class address? C: Only deal with the last octet! –255.255.255.240 –11111111.11111111.11111111.11110000 –How many bits borrowed? 4 2 4 = 16 networks –How many bits left over? 4 2 4 = 16 hosts per sub-network

24. Work Backwards Based on the IP address & SM, identify… –The network address –The broadcast address –How many bits were borrowed –How many bits were left over –Is the address valid

25. What’s Wrong? Are the hosts on the same network or separate?

26. Lab 4.1.5

27. Classless Subnetting CIDR VLSM You can subnet, for each unequal network –Your address is 210.1.17.64 /26 Net A needs 37 hosts Net B needs 15 hosts Net C needs 100 hosts

28. CIDR Block for Router Instead of having multiple subnet entries for each router port, CIDR uses the common bits to make ONE routing table address per port.

29. Running Out of Addresses Private Addresses IPv6 –32 bits NOW 128 bits long! –2 128 which is 3 PLUS 38 ZEROs!

30. NAT Network Address Translation Allows many users to use private IP addresses inside & translates to a pool of public IP’s for travel outside Purpose: –Save public IP addresses –So private IP computers could communicate on the Internet

31. NAT in Action!

32. What’s the Order of NAT? Inside Local IP (Private) goes into your router Translated to an Inside Global IP before exiting Sent across Internet to Outside Local Outside Global sends it back to the Inside Global Your router translates the Inside Global back to the Inside Local (Private) IP

33. Activity

34. Static NAT Static= stays the same Same public IP address maps to a private internal one

35. Static NAT 2

36. Dynamic NAT Has a pool of addresses Translates the private IP to a public & awaits a response –After session is closed, the public IP is returned to the pool of addresses

37. Summary of NAT Static NAT –Outside users need to access inside private network At home, you need to access the mail server –Static private IP is given a static public address Dynamic NAT –Inside private IP host needs to access the public Internet –Selects from a pool of addresses Both can be configured at the same time

38. NAT Review Static NAT works by mapping a specific inside local private IP address to what other specific address type? –Inside global –Outside local –Outside global –Private IP address

39. PAT (or NAT Overload) Port Address Translation Used when you have very few public IP addresses Translates multiple IP’s into a single public –Uses port #’s to keep track of conversations –Uses random source port # above 1024

40. PAT Review Which statement describes NAT overload or PAT? –Each internal address is dynamically translated to an individual external IP address. –A single internal address is always translated to the same external IP address. –Many internal addresses are translated to a single IP address using different port numbers. –Many internal addresses are statically assigned a single IP address and port.

41. PAT Review Which port numbers are used by PAT to create unique global addresses? –255 and below –1024 and below –1025 and above –64,000 and above

42. Lab 4.2.4

43. Review

44. 4: Addressing Working At A Small-to-Medium Business or ISP