Network Addressing Networking for Home & Small Business

Objectives

Purpose of an IP Address Each host needs IP to communicate Assigned to the NIC –Computers, network printer, router interfaces Remember –Packet has source & destination IP

Everything is IP

IP Address Facts Logical (not physical like MAC) IPv4 32 bits, 4 octets –8 bits in each octet – Written in decimal – Value in each octet from –That’s a total of 256 numbers.

Convert binary to decimal Add up the values of the binary 1’s – –229

Binary/Decimal Conversions Practice Binary Game Handout

Parts of an IP Address Network portion Host portion Routers care about network portion

Activity

IP & Subnet Mask Subnet Mask –Helps router decide which network packet is on –Helps show which part of IP is network & host –32 bits – Binary 1’s - ID the network portion Binary 0’s - ID the host portion

What network are these on?

How many hosts- Unsubnetted? SM helps tells us how many hosts are on that network – –Binary 0= identifies # of hosts on that network How many total hosts can be in one octet? –256 –Subtract 2 for useable (.0) is the network ID (.255) is the broadcast address for a network

Binary/Dec/Hex Hex= MAC address 0-9, A-F (10-15) AB

Handout & Lab Lab Homework

Review 1.Which version IP addresses are we dealing with? –IPv4 2.How many bits in an IP address? –32 3.How many octets in an IP address? –4–4 4.Which part of this address is the host portion? –6–6

Review 1.Which network does this belong on? – network 2.How many total hosts can be on that network? Useable? –256 –254, why?

IP Classes & Default SM Class A –Large organizations –1-127 –Default SM= One octet for network, 3 octets for hosts –How many hosts available? 2 24 = over 16 million – –N.H.H.H – –

Class A Example = Class A Default SM for Class A= Network portion of address= 15. Host portion= Network ID= –All zero’s in the host portion Broadcast address= –All binary one’s in the host portion

IP Classes & Default SM Class B –Medium organizations – –Default SM= Two octets for network, 2 octets for hosts –How many hosts available? 2 16 = over 65,000 – –N.N.H.H – –

Class B Example = Class B Default SM for Class B= Network portion of address= Host portion= Network ID= –All zero’s in the host portion Broadcast address= –All binary one’s in the host portion

IP Classes & Default SM Class C –Small organizations – –Default SM= Three octets for network, 1 octet for hosts –How many hosts available? 2 8 = (254 useable) – –N.N.N.H – –

Class C Example = Class C Default SM for Class C= Network portion of address= Host portion=.89 Network ID= –All zero’s in the host portion Broadcast address= –All binary one’s in the host portion

Other IP Classes & More Class D & E not for commercial use –D is multicast (one to a group) – All 0’s in host portion(s) = network ID All 1’s in host portion(s)= broadcast CAN NOT USE THOSE FOR HOSTS! Activity on 5.2.1

Handouts Lots of Practice!

Public/Private IP’s Some addresses are reserved & can not be routed across Internet You can have a public IP for network/servers & private for hosts inside –Saves IP addresses Address Class Address Range A B C

Private IP’s If host does not connect DIRECTLY to Internet, it can have a private IP Router BLOCKS private IP’s Security!!! –Private IP’s can not be seen from Internet range is reserved for loopback testing

Private Nets Activity

Unicast Communication One-to-one or Source to destination

Broadcast Communication One-to-all or Source to all in segment All hosts will look at it All 1’s in host portion(s) of address Broadcast IP & MAC Default Broadcasts –A –B –C

Broadcast Communication

Multicast Communication One-to-group Class D Multicast MAC begins with E Where is it used? –Gaming –Distance learning

Multicast Communication

Which one? Unicast Multicast Broadcast

Activity & Handout Handout DOS –Netstat –e –Do this every 10 seconds –Pay attention to non-unicast packets

Review ; What network is this on? – Which default SM has the most hosts? –Class A –Over 16 million! 3.How many useable hosts in a Class C? – ; What network is this on? –

Review 1.What are the private IP addresses? –10, , What is the MAC broadcast frame in hex? –FF-FF-FF-FF-FF-FF 3.What is the MAC for a multicast? – E 4.One to one communication is… –Unicast 5.To send a unicast message, which addresses do you need? –Source & dest. IP & MAC

Assigning IP Addresses Static –Manually type in IP Address –Good for printers or servers Devices people access all the time You wouldn’t want their address changing! –Good documentation!!!!

Assigning IP Addresses Dynamic –Assigned auto by DHCP server –Assigns IP, SM, DG, more –Good for larger networks or with mobile/new devices –Leased addresses

Assigning IP Addresses Admins have a pool of IP addresses –DHCP assigns from the pool SOHO routers usually have DHCP Medical field- –Legal requirement –Must track who is on machine –DHCP server assigns & keeps log of users

DHCP Servers How you get on the net in a hotel, Starbucks, or BK Either dedicated server or mixed in another device –From ISP or on your ISR

How DHCP Works

Configuring DHCP on Linksys Packet Tracer Lab

Review 1.Which addresses does a host use to discover a DHCP server? – –FF-FF-FF-FF-FF-FF 2.Who sees that? Who responds? –All on the segment –The DHCP server 3.What happens to a PC’s IP when you shut down? –Goes back to the DHCP pool of addresses

Network Boundaries

The Network In & Out

How to Connect to the ISP Directly –1 PC to a modem –PC gets address from ISP ISR –Modem to ISR –Internal PC’s get addresses from ISR Gateway Device –ISR & Modem in one –Internal gets private IP’s

NAT Translates private into public addresses Prevents external from seeing internal A private (local) source IP address is translated to a public (global) address. –The process is reversed for incoming packets. –The integrated router is able to translate many internal IP addresses to the same public address, by using NAT.

NAT Example

Packet Tracer

Review 1.Which address does the PC need to access the Internet? –Default gateway address of the ISR 2.Which devices translates NAT? –ISR

Review

Network Addressing Networking for Home & Small Business