Using Nmap to Calculate Network Response Time

Nmap stands for Network Mapper. It is a tool, primarily used for Port scanning, to check vulnerabilities, and of course, the main purpose - Network Mapping. Most popular Linux distributions give you full root access to their distribution by default but it's easy to configure otherwise; only remember to always add Nmap as an interactive shell before your machine starts up (not just nmap ). You should never try this at home without doing some research first! Once installed simply run: sudo apt-get install nmap. This will perform various checks which usually means that there are no existing security issues in /etc/rc.local or all files listed below have been reviewed via scans performed manually prior launch process being known about.

What is Network Response Time?

Network response time is the time taken by the packet to travel from the User to Receiver. When N/W (Network) Response time is high, performance can be impacted. As you might imagine it would make sense that an ISP that has poor internet connectivity could see their advertised download speed decline as they move between devices in their infrastructure on a consistent basis. While this happens naturally when connection speeds are not reliable and there are low upload/download links available at all times. This phenomenon only comes into play if such congestion exists prior. Theoretically, these changes cannot result without some sort (notably increased peak capacity) but due to the lower overall bandwidth requirements and other factors, I believe networks will continue adjusting slightly around them. Maintaining constant throughput per device connection may need tweaking depending on your application usage patterns.

Installation of Nmap on Linux:

Nmap is typically available in most Linux distributions' repositories. To install it, we can use the package manager specific to our distribution.

For instance, on Debian-based systems, we can use:

sudo apt-get install nmap

On Red Hat-based systems, we can use:

sudo dnf install nmap

Calculating NRT using Nmap

Network Response Time (NRT) serves as a pivotal metric for evaluating network performance, as it directly reflects the efficiency of communication within a network. In this pursuit, Nmap, a versatile and renowned network scanning tool, offers an array of scanning options tailored to efficiently measure NRT. In this exploration, we delve into the mechanics of calculating NRT using Nmap and elucidate the command syntax, supplemented by a practical example. With NRT being a vital indicator of network responsiveness, our examination aims to provide comprehensive insights into harnessing Nmap's capabilities for gauging this essential performance parameter.

Nmap Scanning Options for NRT Measurement

Nmap offers several scanning options, such as TCP SYN Scan, TCP Connect Scan, and UDP Forward Scan, to measure NRT. For our purpose, we'll focus on the TCP SYN Stealth Scan, commonly known as the SYN Scan.

Command Syntax:

 nmap -[advanced commands] IP

Command Example: 

sudo nmap -sS -Pn -n -p80 -d3 www.geeksforgeeks.com

• -sS: Specifies a SYN Stealth Scan, a type of port scan where only SYN packets are sent to the target.
• -Pn: Disables host discovery, treating all provided IP addresses as "up."
• -n: Disables DNS resolution, preventing Nmap from attempting to resolve IP addresses to hostnames.
• -p80: Specifies scanning only port 80 (HTTP).
• -d3: Enables debugging output level 3, which provides detailed information about the scan process.

In this example, we perform a SYN Stealth Scan on port 80 of the website "www.geeksforgeeks.com." The output will display detailed information about the scan process, timing, and response time.

Understanding the Output:

• The output will show the target host's IP address, along with port 80 (HTTP) being open.
• You will also see timing statistics, including values like srtt (smoothed round-trip time) and rttvar (round-trip time variation). These values help estimate the network response time.

Network response time can be approximated using the srtt value, indicating the smoothed round-trip time. Keep in mind that NRT calculation involves multiple factors, and the provided values offer insights into the responsiveness of the network. By using Nmap's scanning options and analyzing the output, you can effectively measure network response time and gather valuable information for network performance assessment.

Here, we get the final time for host srtt - 5416. This means approximately RTT is 5.416ms. We also get the Timing report along with this.

We have got the results of our scan on the target URL "www.geeksforgeeks.org"