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How to do Reconnaissance Phase of Penetration Testing?

Ayush Mania
Ayush Mania
  • Mar 8, 2024
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    10 min read
How to do Reconnaissance Phase of Penetration Testing?
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Reconnaissance is the cornerstone of any successful penetration testing strategy. This crucial phase involves gathering information about the target environment, enabling penetration testers to identify vulnerabilities and potential entry points. In this comprehensive guide, we will walk through various reconnaissance techniques and tools, providing a step-by-step approach for both beginners and intermediate penetration testers.

Google Dorking

Google Dorking refers to the practice of using advanced search operators in Google's search engine to discover specific information that is not easily accessible through conventional searches. This technique is often employed by security professionals, researchers, and hackers to find vulnerabilities, exposed sensitive information, or other details that may be hidden from regular search queries. Here’s the table for detailed Google Dorking operators and its example.

Operator Working
site Restrict the search to the specified website

site: → This will show pages that are on only.
intitle Search for the pages containing the given term in the titles of the web pages

intitle: testing site: → This will show pages that contain “testing” in the page title on website only.
allintitle Shows results of pages containing all the query terms specified in the title only

allintitle: BMW sports → Returns only pages containing words “BMW” and “sports”
inurl Restricts the results to pages containing the word specified in the URL

inurl: copy site: → Returns pages in site in which the URL has the word “copy”
allinurl Restricts the results to pages containing all the query terms specified in the URL

allinurl: pen test → Returns only pages containing the words “pen” and “test” in the URL
inanchor Shows pages containing the query terms specified in the anchor text on links to the page only

security inanchor: alphabin → Returns pages with anchor text on links containing “alphabin” and the page containing “security”
allinanchor Search for the pages only containing all query terms specified in the anchor text on links to the page

allinanchor: best offensive security provider → Gives pages in which the anchor text on links to the pages contain the words “best”, “offensive”, “security”, and “provider”
cache Allows to view the cached version of the web page

cache: → Gives cached version of
filetype Search for specified filetypes only

Alphabin filetype: pdf → Returns PDF files on target Alphabin
link Search for the pages that contain links to the specified website or page

link: → Find pages that point to Alphabin Services’s home page
related Displays websites that are similar or related to the URL specified

related: → Provides the Google search engine page with websites similar to
info Finds information for the specified web page

info: → Gives information about the national hotel directory home page
location Finds information for specified location

location: Buddha’s hut → Gives the results based around the term Buddha’s hut

The Harvester

The Harvester is a versatile tool designed for harvesting information from various sources. It is developed by the Christian Martorella at Edge Security. Let’s learn how to use it effectively to collect emails, subdomains, and other valuable data.

The Harvester is a Python script, so ensure you have Python installed and the pip package manager. Then, install The Harvester using,


The basic command structure is,


where domain is your target and source is the data source (e.g., Google, Bing, PGP).

Understand it better with an example, To collect emails and subdomains from "" using Google and Bing, run,


The Harvester supports various sources like search engines, social media, PGP servers, and more. There is much more to the harvester to explore. You can find much more interesting functionalities of theHarvester. 


Whois lookup provides details about domain registration, including contact information. Tools like Whois databases and online services such as Whois Lookup can help gather information about the target domain. It can be done using online web applications like Whois Domain Tools, or it can be done using the command line on your machine. Here’s the example of whois record of using Whois Domain Tools:

This same records can be fetched using command line utility as well, just we have to use whois command following with domain name. Example, issuing whois will return the results shown in the picture below.

Before moving further, the same information can also be extracted using Netcraft as well. Actually, Netcraft provides more than just domain information; it searches the whole web to find any related information to a given domain name, including Site Background, Host History, Sender Policy Framework and much more. Let’s see how we can get this information easily using Netcraft.

Enter the target’s domain address and start the search. It will show you the domains related to the keywords you provided. Here its showing me two web addresses for the,

You may get different results based on your searching keywords. One thing to notice here is, Netcraft has provided us with the OS of the server on which the website is hosted. This is very important information to do penetration testing, because if the OS is Linux and you are exploiting it with Windows exploits; you will never get any desirable result. Now, let’s go further and look into the details of “”. You can see it from the site report.

You are provided with site background, which is giving information like site rank, when it has been first seen on the internet, language of the website, and etc. In the network section, it's giving us domain details and IP addresses related to the domain. And on scrolling down you will see hosting history, SSL/TLS information, web trackers and even site technologies used.

Upto this point, we may have DNS server IPs, Name Servers or both. But what if we are not having the IP of a given domain or web server. No worries, there is a solution for it too. Let’s take a look at the solution, Host.


The 'host' command in Linux is a powerful tool for DNS reconnaissance. Learn how to use it to obtain information about a target's DNS records and IP addresses. It is a versatile command-line utility that provides various DNS-related information. It can map domain names into IP addresses and vice-versa using DNS caches and tables. Here are some common uses of the 'host' command,

Function Command Description
Basic DNS Lookup host This command retrieves the IP address associated with the domain name "".
Reverse DNS Lookup host This command performs a reverse DNS lookup to find the domain name associated with the given IP address.
Querying a Specific DNS Record Type host -t mx This command retrieves the Mail Exchange (MX) records for the specified domain.
Name Server Lookup host -t ns This command fetches the name servers responsible for the specified domain.
Verbose Output host -v This command provides more detailed information, including the query process and additional DNS record types.
Querying a Specific DNS Server host This command directs the query to a specific DNS server (in this case,
Checking Mail Exchange (MX) Records host -t mx This command fetches the Mail Exchange (MX) records for the specified domain, which are used for email routing.
Displaying All DNS Record Types host -a This command retrieves all available DNS records for the specified domain.

Other ways you can gather information is using Open Source Intelligence (OSINT) framework and Social Engineering. You can get details on OSINT and Social Engineering from here.


Effective reconnaissance involves sifting through vast amounts of information to identify potential attack vectors. For effective penetration testing, learn how to prioritize and filter intelligence for actionable insights. Practical hands-on experience is crucial for mastering reconnaissance. Discover realistic scenarios, labs, and platforms for honing your skills. Some of the very good online platforms to learn Ethical Hacking and Penetration Testing are HackTheBox and TryHackMe.

Reconnaissance is just the beginning. The further journey of Penetration Testing is much more interesting compared to Reconnaissance. As a beginner, it's good practice to keep Recon and Scanning different, but as you gain more knowledge and experience, you may treat both of them together.

Alphabin also provides complete penetration testing including a dedicated phase and engineer for reconnaissance during testing to ensure security of your information and integrity of business.

Read the next chapter

Frequently Asked Questions

How does Reconnaissance differ from other phases of penetration testing?
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Unlike other phases that may involve active engagement with the target’s systems, reconnaissance is typically passive. Testers collect information without directly interacting with the target’s systems to avoid detection and to simulate an attacker’s initial information-gathering stage. Simultaneously, attacker can engage with person related to target and collect information via social engineering as well. Ultimately, recon is the data gathering phase which doesn't include much technicality than other phases of pentest.

How do penetration testers ensure they remain undetected during reconnaissance?
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Testers use a variety of tactics to stay hidden, including:

  • Using proxy servers and VPNs to mask their IP addresses.
  • Timing their activities to blend in with normal traffic patterns.
  • Using publicly available information without directly engaging the target.
Is reconnaissance a one-time activity in penetration testing, and can it be automated?
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While reconnaissance is the initial phase, it’s not a one-time activity. Testers may return to this phase as needed throughout the penetration test to gather additional information or to explore new leads as they emerge.

Both automated tools and manual techniques are used. Automated tools can quickly gather large amounts of data, while manual methods allow for targeted, in-depth research on specific areas of interest.

What challenges do testers face during the reconnaissance phase?
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Challenges faced during reconnaissance include:

  • The vast amount of data available makes it difficult to identify what is relevant.
  • There is a need to distinguish between outdated and current information.
  • Avoid alerting the target or triggering security measures.

About the author

Ayush Mania

Ayush Mania

Ayush Mania, an offensive security specialist at Alphabin, specializes in securing web applications and servers. With his expertise in penetration testing and red teaming, he leverages diverse security techniques to identify and fix vulnerabilities. A passionate learner, Ayush enjoys collaborating to achieve shared goals.

More about the author
Join 1,241 readers who are obsessed with testing.
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