introductory lab assignment

Manolis Surligas (CSD, UoC) Introductory Lab Assignment March 3, 2015 1 / 12

Introductory Lab AssignmentComputer Science Department, University of Crete

Manolis Surligas [email protected]

March 3, 2015

mailto:[email protected]

Outline

1 Goal of the first assignment

2 Lab equipment

3 Software Tools

4 Hardware needed for the first assignment


Goal of the first assignment

• Prepare the environment that you are going to work (PCs, OSetc)

• Get familiar with different fundamental network software tools

• Use different hardware equipment and understand their keyfeatures

• Play with the parameters of the hardware/software and observeperformance changes


Lab equipment

• The Lab provides several computers that are connected together

• This year we going to use a native installation of a Linuxdistribution

• The distribution is a custom variant of openSUSE(https://www.opensuse.org)

• Tools for development, network monitoring, testing and securityare already installed

• More that 3 graphical desktop environments to choose!

Note!

If you need more packages or tools contact the TA or the instructors


https://www.opensuse.org

Software Tools

• In order to accomplish your tasks several software tools arenecessary

• It is essential to get familiar with them

• Many of them are not required by the assignments but are vitalfor troubleshooting and debugging (e.g. nmap, wireshark)

• Some of them:• ifconfig :ip• iperf :iperf3• tcpdump• iftop• netstat• nmap• ping

• ethtool• traceroute• route• arp• arping• wireshark• And many, many others


The ip tool

• ip is a tool for configuring network interfaces and get informationabout them

• For kernels before 2.2 ifconfig was used

• It frequently used to statically assign the IP and the subnet of ahost

Note!

The networks that you are going to setup at the lab assignments, donot have a DHCP to automatically provide IP addresses, so you haveto assign statically IPs using ip!

Hint!

Every time you unplug a cable, the IP address settings are lost, so youhave to apply them again!


The ip tool

• Lets see some examples!

• To show the available network interfaces use the command:

• To assign the 192.168.1.203 IP address in a /24 subnet at theinterface eth1 you can use the command:

• For more info man ip or ip OBJECT help


The nmap tool

• nmap is a network exploration tool

• Scans a given range of IP addresses and/or ports

• Very useful in cases that we do not know the IP of a device

• We can get the number of connected hosts in a network

• We can get also the services that end hosts are running


The ethtool

• ethtool is used to query and control network device driver andhardware settings, particularly for wired Ethernet devices

• Can disable or enable offloading capabilities of network interfaces• Offloading refers to operations that are implemented on hardware

(e.g. CRC calculation and checking)• Critical for high performance

• Very useful to set a fixed speed (10 Mbps, 100 Mbps e.t.c.) andoperation mode (full Duplex, Half Duplex)


The iperf3 tool

• iperf3 is a tool for performing network throughput measurements

• Operates in a server-client model

• Measurements can be performed using TCP or UDP

• Server receives the traffic originated from the client

• Always take into consideration the throughput report of theserver

• Why?


Hardware needed for the first assignment

• For the first assignment you have to use two different networkdevices

• A Hub• A 8-port Cisco SLM2008 1 Gigabit managed switch

• Default configuration IP: 192.168.1.254• Username and Password: admin

Attention!!

Take care of the power supplies!!!! The Cisco switch uses 12V DCadapter whereas the Hub uses a 12V AC adapter!!

Note!

When you finished with your work, reset every device in the defaultsettings and connect the computers at their initial network setup.


Hardware needed for the first assignment

• Prefer to use the already installed Ethernet cables

• All of them end up to the main Ethernet switch, located left ofthe Whiteboard

• Each cable has a label of the computer that corresponds

• Respect other users of the lab. When finished, restore theconfigurations and place the cables back to their places.

• In case of hardware failure, inform the TA or the instructors


introductory lab assignment

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