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Computer Maintenance Software(CM274)

Chapter 3:Network Protocols & TCP/IP Utilities

Prepared by Eisa Haider

Supervised by Meshal Al-Dhamen

(Oct., 2015)

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Network Protocols

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Network Protocols

• Network Protocols provide link services, handle addressing and routing,error checking, and retransmission requests.

• Examples:• IP (Internet Protocol): Packet forwarding and routing.

• IPX (Internetwork Packet Exchange): Novell's protocol for packet forwarding and routing.

• NWLink: Microsoft's implementation of Novell's IPX/SPX protocols.

• NetBEU: Transport for NetBIOS sessions and applications.

• DDP (Datagram Delivery Protocol): An AppleTalk data transport protocol.

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TCP/IP

TCP/IP (Transmission Control Protocol/Internet Protocol) is the basiccommunication language or protocol of the Internet. It can also be used asa communications protocol in a private network.

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IP Addressing

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IP Addressing

• An IP address is a unique identifier for a node or host connection on anIP network.

• There are two versions of the Internet Protocol (IP) are in use: IP Version4 (IPv4) and IP Version 6 (IPv6).

• Each version defines an IP address differently.

• Because of its prevalence, the generic term IP address typically still refersto the addresses defined by IPv4.

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IP Addressing

• An IP address is a 32 bit binary number usually represented as 4 decimalvalues, each representing 8 bits, in the range 0 to 255 separated bydecimal points.

• Example:• 140.179.220.200

• 10001100. 10110011.11011100.11001000

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IP Addressing

• Every IP address consists of 2 parts, one identifying the network, andone identifying the node.

• The class of the address and the subnet mask determine which partbelongs to the network address and which part belongs to the nodeaddress.

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Address Classes

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Address Classes

• There are 5 different address classes. You can determine which class anIP address is in by examining the first 4 bits:

1. Class A addresses begin with 0xxx, or 1 to 126 decimal.

2. Class b addresses begin with 10xx, or 128 to 191 decimal.

3. Class C addresses begin with 110x, or 192 to 223 decimal.

4. Class D: Multicast.

5. Class E: Research.

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Address Classes

• Addresses beginning with 01111111 or 127 decimal (127.0.0.0 to127.255.255.255), are reserved for loop back and for internal testing ona local machine.

• Test this:You should always be able to ping 127.0.0.1, which points to yourself.

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Address Classes

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Address Classes

Now you can see how the Class determines, by default, which part of theIP address belongs to the network and which part belongs to the node.

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Address Classes

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Class Number of Networks Number of Hosts

A 126 16,777,214

B 16,384 65,534

C 2,097,152 254

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Private Subnet

• There are 3 IP network reserved for private networks. The addresses are:• 10.0.0.0/8

• 172.16.0.0/12

• 192.168.0.0/16

• They can be used by anyone setting up internal IP networks, such as a lab orhome LAN.

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Subnet Masking

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Subnet Masking

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• Applying a subnet mask to an IP address allows you to identify thenetwork and node parts of the address.

• The network bits are represented by the 1s in the mask, and the nodebits are represented by the 0s.

Subnet Masking

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• Performing bitwise logical AND operation between the IP address andthe subnet mask results in the Network Address or number.

• For example, using our test IP address (140.179.240.200) and thedefault Class B subnet mask, subnet mask, we get:

10001100.10110011.11110000.11001000 140.179.240.200 Class B IP Address

11111111.11111111.00000000.00000000 255.255.000.000 Default Class B Subnet Mask

10001100.10110011.00000000.00000000 140.179.000.000 Network Address

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Subnet Masking

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140.179.240.200

255.255.000.000

140.179.000.000

Default Subnet Masks

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Class A 255.0.0.0 11111111.00000000.00000000.00000000

Class B 255.255.0.0 11111111.11111111.00000000.00000000

Class C 255.255.255.0 11111111.11111111.1111111.00000000

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TCP/IP Utilities

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TCP/IP Utilities

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1. TRACERT.

2. PING.

3. ARP.

4. NETSTAT.

5. IPCONFIG.

6. NSLOOKUP.

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1. TRACERT

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• TRACERT can be used to trace the path that an IP packet takes to itsdestination.

• TRACERT uses ICMP Echo packets and their TTL to determine the routeand hope count.

• When a connection between host A and B fails, you can use TRACERT tofind out where the packet stopped.

• The target can be either a name or an IP address.

1. TRACERT

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1. TRACERT

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Use TRACERT -d to turn off host name resolving which speeds up thetracing.

2. PING

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• PING utility is a diagnostic tool that you can use to test TCP/IPconfiguration and connections.

• Use the PING utility to determine whether a particular TCP/IP host isreachable or available.

• The target can be either a name or an IP address.

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2. PING

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Some common situations where PING can be used:

1. To verify that TCP/IP has been initialized and is correctly installed byusing ping command with the loopback address (127.0.0.1).

2. To verify that the default gateway is available and that the computercan communicate with a remote host through a router by pinging ahost on a remote network.

2. PING

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3. To verify that DNS host name resolution is available by pinging anexisting host name.

4. To verify that WINS name resolution is available by pinging an existingNETBIOS name.

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2. PING

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3. ARP

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• The ARP (Address Resolution Protocol) is used to resolve an (Layer 3) IPaddress to a (Layer 2) MAC address.

• The ARP utility provides the functionality to modify or display the ARPcache table.

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1. ARP

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Use ARP -a to display current ARP entries.

4. NETSTAT

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• NETSTAT displays TCP/IP protocol statistics and information about TCPand UDP connections to and from your computer.

• Use NETSTAT –a to display all the connections and listening ports.

• Use NETSTAT –e to display Ethernet statistics, such as the number ofbytes and packets sent and received.

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4. NETSTAT (NETSTAT –a )

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4. NETSTAT (NETSTAT –e )

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5. IPCONFIG

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• IPCONFIG displays TCP/IP configuration information and renew andrelease DHCP assigned address configuration.

• Using IPCONFIG /All displays full configuration information.

5. IPCONFIG

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6. NSLOOKUP

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• NSLOOKUP displays information that can use to diagnose Domain NameSystem (DNS) servers and to send DNS queries to DNS servers.

• NSLOOKUP can be used in interactive (without options) and non-interactive mode.

6. NSLOOKUP (Interactive Mode)

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6. NSLOOKUP (None-Interactive Mode)

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