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Objectives
Describe the IP address structureIdentify network classesObtain a registered IP addressRegister a Domain nameAssign addresses to hostsDescribe how host names, host tables, and DNS work
Objectives (con’t)
Describe Windows Internet Name Services (WINS)Describe how ports are usedExplain the purpose of subnetsDefine a subnet maskDescribe how subnet masks are usedAssign subnet addresses
IP Address Structure
4 bytes or 32 bits called a “dotted quad”Comprised of a network ID and a host IDHost is a server, workstation, or other node
Routers on Internet route messages to the Network ID portionOnce message gets to correct network, it is delivered based on the node address
IP addresses
172.16.4.2– Base 10 numbers
10101100.00010000.00000100.00000010– Binary number system
Same address
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
Network ClassesClass 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
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
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
Obtain a Registered IP Address
InterNIC or Network SolutionsARIN American Registry for Internet NumbersRIPE Reseaux IP EuropeansAPNIC Asia Pacific Network Information Center
Addresses are given to major ISPs, who assign numbers to their customers
Register a Domain Name
My business name is “Technology Trainers”I “own” www.technologytrainers.com
Registered the name, pay InterNIC a fee for a “business card” at that location to hold the name.Renew every 2 years
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 ??
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
Private Network Addresses
Filtered out by Internet routers (RFC 1918)Class A 10.0.0.0 to 10.255.255.255Class B 172.16.0.0 to 172.31.255.255Class C 192.168.0.0 to 192.168.255.255
If you are connected to the Internet, you must use registered addresses!
Host Tables
Internet-Address official-host-name aliases132.132.87.176 argo132.132.12.45 pacific pa132.132.19.42 sales.vax127.0.0.1 loopback #loopbackDNS server resolves names by referring to table
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
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 defaultMask is a dotted quad number, logically ANDed with the IP address to identify which bits are network and which are host or node addressAny bit that is part of the network address has a “1” value in the subnet mask
Default MasksDefault masks do no additional subnettingClass A 11111111.00000000.00000000.00000000 255.0.0.0 or FF.0.0.0Class B 11111111.11111111.00000000.00000000 255.255.0.0 or FF.FF.0.0Class C 11111111.11111111.11111111.00000000 255.255.255.0 or FF.FF.FF.0
# of Subnet bits
Possible subnet addresses (Binary)
Byte in corresponding subnet mask
Possible subnet addresses
1 1 000 00000 000 0000
1 000 0000 128*0*
2 11 00 000010 00 000001 00 000000 00 0000
11 00 0000 192*128640*
3 111 0 0000110 0 0000101 0 0000100 0 0000011 0 0000010 0 0000001 0 0000000 0 0000
111 0 0000 224*1921601289664320*
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
2 2n
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 maskRouters within the network apply the subnet mask
Partial bytes as subnets
Book Example page 7-40Class C address, subnet mask of 255.255.255.2245 bits left for host
hosts30)2)32(()2)2(( 5
Subnetted Class C
Masked bits
Binary Decimal Subnets Hosts
1 1000 0000 128 2 1282 1100 0000 192 4 643 1110 0000 224 8 324 1111 0000 240 16 165 1111 1000 248 32 86 1111 1100 252 64 47 1111 1110 254 128 2
Assign Subnet Addresses
Each address must be uniqueNetwork and subnet numbers must be the same for all devices on the same networkThe Host portion of the address cannot be all [1]s or [0]s
Plan for growthDon’t use reserved addresses
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?
Assigning Addresses
Assign subnets from the left most bitAssign hosts from the right most bitThis leaves a buffer zone between hosts and subnets, for future useSee page 7-46Subnet Calculator www.net3group.com/download.html-ssi
Steps for creating subnetsDetermine the number of subnets you needDetermine your subnet mask and subnet addressesAssign IP addresses to each host on a subnetFormulas (page 7-49)– n=number of masked address bits– m=number of unmasked address bits
hosts
subnetsm
n
22
22
Determine the number ofsubnets you need
Keep in mind growthBook example 6 subnets are needed now, but they reserved the entire third byte for future needsThis gives growth possibility of 254 subnets
Determine Subnet Mask and Subnet Addresses
Determine the number of available subnet address values and the number of available host address values per subnetClass B address, 3 masked bits (255.255.224.0)–
hosts
subnets
819022
62213
3
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 valueAdd Delta to the previous value to determine the next subnet valueContinue until the value is >254Example on page 7-51/52
Assign IP Addresses to each hostBook example page 7-53All addresses must be 132.132.x.yX 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
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