Assignments3 - Networking in Linux
Contents |
TCP/IP
Some information regarding the document Tcp-ip-s1.pdf.
This document is outdated but it doesn’t matter, the principle about TCP/IP and networking is still the same and it is an excellent document to start with.
The document will only cover IPv4.
We will only focus in chapter1: Introduction to TCP/IP.
Here are a couple of questions that I want you to answer as best as you can.
You need of course to read chapter1 carefully and understand the content.
If you are struggling to understand some part of it don’t hesitate to contact me.
Questions
- Why do we need a standardisation in the computer industry?
- What was the purpose of TCP/IP in the beginning?
- Who started the Internet and why?
- What is the biggest difference between TCP/IP and other protocols?
- What is the OSI Model and why it was invented?
- Which layers does TCP/IP uses in the OSI model?
- Why is it so important to understand the OSI model and its layers?
- What does binary form means?
- What is the decimal equivalent of 11101110? Explain how you calculate the answer.
- Why do we use a subnet mask?
- How many IP addresses IPv4 are available?
- What is an ISP?
- What is special with the IP address 127.0.0.1?
- What is the alternative names of 127.0.0.1?
- Give example of class A, B, C IP addresses.
- The number of IP addresses are limited, what is the solution to this problem?
- Read the document Subnet_calculation.pdf. What is the answer for the network 192.168.8.0/27 ?
- What is a TCP/IP packet?
- What is a packet switch network?
- What happens when some packet are lost during the data transfer?
- What is the role of TCP?
- How may bits is the TCP/IP header?
- What is the function of Identification flag in the header?
- What is TTL?
- Give some examples of other protocols.
- What service and port number did you use to remote connect to Linux?
- What is the difference between reserved and privileged ports?
- If you are able to login to your home router, what kind of information you can gather?
- Suppose that you can’t access google.com from your browser, what are the steps that you need to take to troubleshoot and what are the commands that you can use?
Networking in Linux
The files that the system uses to be able to access the network are:
/etc/network/interfaces
This file contains information about which method the system is using to get its IP address, by using DHCP service (more about this later) or by using static IP address.
If the system is using the DHCP service the parameters will not be visible. However if the system will use static IP address the following parameters are needed in the file:
- iface eth0 inet
- address
- netmask
- network
- broadcast
- gateway
- Dns-nameservers
Check the content of this file. What do you see?
/etc/resolv.conf
This file contains information about DNS.
Without this file you can’t get to google.com or facebook.com etc..
/etc/hosts
This files contains information about the local hostname and it’s IP address.
/etc/hostname
This files contains information about the local hostname.
Change the IP address of the Linux machine to static IP address and change the hostname to eniac01.
Test some network tools
To troubleshoot a network problem in your network environment you need to know how to use network tools in Linux.
Read the document Quick-HOWTO-Simple Network Troubleshooting.pdf and test the following commands. Fill in the Purpose and Example in the table.
| Command | Purpose | Example with result in your machine |
|---|---|---|
| ifconfig | ||
| mii-tool | ||
| ethtool | ||
| arp | ||
| ping | ||
| telnet | ||
| curl | ||
| mtr | ||
| tcpdump | ||
| nslookup | ||
| host | ||
| nmap | ||
| nc |
Report
Send me your answers in an ASCII file.
