Book Image

Securing Network Infrastructure

By : Sairam Jetty, Sagar Rahalkar
Book Image

Securing Network Infrastructure

By: Sairam Jetty, Sagar Rahalkar

Overview of this book

Digitization drives technology today, which is why it’s so important for organizations to design security mechanisms for their network infrastructures. Analyzing vulnerabilities is one of the best ways to secure your network infrastructure. This Learning Path begins by introducing you to the various concepts of network security assessment, workflows, and architectures. You will learn to employ open source tools to perform both active and passive network scanning and use these results to analyze and design a threat model for network security. With a firm understanding of the basics, you will then explore how to use Nessus and Nmap to scan your network for vulnerabilities and open ports and gain back door entry into a network. As you progress through the chapters, you will gain insights into how to carry out various key scanning tasks, including firewall detection, OS detection, and access management to detect vulnerabilities in your network. By the end of this Learning Path, you will be familiar with the tools you need for network scanning and techniques for vulnerability scanning and network protection. This Learning Path includes content from the following Packt books: •Network Scanning Cookbook by Sairam Jetty •Network Vulnerability Assessment by Sagar Rahalkar
Table of Contents (28 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
Index

How to identify open ports


The following are the six port states that are present in Nmap:

  • open: This means that the port is functioning and has a service running or accessing it. The service can thus accept any connections made as per the protocol and service in use on this port.
  • closed: A closed port is not being accessed by any service, there is no service running on it. Thus, no connections made externally will be successful on these ports.
  • filtered: This status is associated with ports from which no response was received due to the packet filtering mechanism present within the network.  This might be caused by an intermediate network protection device.
  • unfiltered: This status is associated with the ports that Nmap was not able to determine whether they were open or closed. Mostly ACK scan labels ports to be in unfiltered state; moreover, scans such as SYN and FIN can help resolve such issues.
  • Open|filtered: Nmap classifies ports with this type when no response is received from them. The...