Practical • Demonstrate the use of Network tools: ping, ipconfig, , tracert, arp, , whois • Perform encryption and decryption of Caesar cipher. Write a script for performing these operations. • Perform encryption and decryption of a Rail fence cipher. Write a script for performing these operations. • Use nmap/zenmap to analyse a remote machine. • Suggested Reading: [2] Chap 3 (Nmap) • Use Burp proxy to capture and modify the message. • Demonstrate sending of a protected word document. • Demonstrate sending of a digitally signed document. • Demonstrate sending of a protected worksheet. Ping • The ping is a Command Prompt command used to test the ability of the source computer to reach a specified destination computer. The ping command is usually used as a simple way to verify that a computer can communicate over the network with another computer or network device. • The ping command runs in a Windows Command Shell and has a very basic syntax it’s core: • ping domain_name • Ping Command Syntax • ping [-t] [-a] [-n count] • -t Using this option will ping the target until you force it to stop using Ctrl-C. • -a This ping command option will resolve, if possible, the hostname of an IP address target. • -n count This option sets the number of ICMP Requests to send, from 1 to 4294967295. The ping command will send 4 by default if - n isn't used. ipconfig

• ipconfig is a command line utility available on all versions of Windows starting with Windows NT. ipconfig is designed to be run from the Windows command prompt. This utility allows you to get the IP address information of a Windows computer. • From the command prompt, 'ipconfig' to run the utility with default options. • The output of the default command contains the IP address, network mask and gateway for all physical and virtual network adapters. • ipconfig supports several command line options as described below. The command "ipconfig /?" displays the set of available options. • ipconfig /all • This option displays the same IP addressing information for each adapter as the default option. Additionally, it displays DNS and WINS settings for each adapter. Ifconfig

• ifconfig is a system administration utility in - like operating systems for network interface configuration. • Ifconfig is used to configure the kernel-resident network interfaces. It is used at boot to set up interfaces as necessary. After that, it is usually only needed when debugging or when system tuning is needed. • If no arguments are given, ifconfig displays the status of the currently active interfaces. • If a single interface argument is given, it displays the status of the given interface only; if a single -a argument is given, it displays the status of all interfaces, even those that are down. Otherwise, it configures an interface. WHOIS

• WHOIS is a query and response protocol that is widely used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name, an IP address block, or an autonomous system, but is also used for a wider range of other information. The protocol stores and delivers database content in a human-readable . • http://whois.domaintools.com/ tracert

• The tracert command is a Command Prompt command that's used to show several details about the path that a packet takes from the computer or device you're on to whatever destination you specify. • Tracert [-d] [-h MaxHops] [-w ] -4 -6 • d = This option prevents tracert from resolving IP addresses to hostnames, often resulting in much faster results. • -h MaxHops = This tracert option specifies the maximum number of hops in the search for the target. If you do not specify MaxHops, and a target has not been found by 30 hops, tracert will stop looking. • -w TimeOut = You can specify the time, in milliseconds, to allow each reply before timeout using this tracert option. • -4 = This option forces tracert to use IPv4 only. • -6 = This option forces tracert to use IPv6 only.

• Network administrators and system administrators use this tool most commonly in their day to day activities. Its basically a network diagnostic tool that is very handy. There are three main primary objectives of traceroute tool. These objectives fulfilled by tracroute gives an insight to your network problem. • The entire path that a packet travels through • Names and identity of routers and devices in your path • Network Latency or specifically the time taken to send and receive data to each devices on the path • Each IP packet that we send on the internet has got a field called as TTL. TTL stands for Time To Live. TTL is measured by no of hops i.e. the maximum number of hops that a packet can travel through across the internet, before its discarded.Traceroute makes use of this TTL to out routers that come across the path to destination • eg traceroute -n 8.8.8.8 which is google's publicly available DNS server(8.8.8.8)