DNS info Fetcher

This article explains a powerful C++ script that queries DNS records and WHOIS information for any domain.

What the Script Does

The C++ script is designed to fetch DNS records (such as A, AAAA, MX, TXT, etc.) from multiple DNS servers and retrieve WHOIS information for a given domain. It executes the following steps:

Queries DNS records for various types using the nslookup command.
Executes queries against multiple DNS servers (e.g., 8.8.8.8, 1.1.1.1).
Interprets specific DNS record types like SPF in TXT records and mail exchange servers in MX records.
Fetches WHOIS information for the domain and appends the results to the output file.
All output is saved to a file specified by the user.

How to Use the Script

To use this script, follow these steps:

Make sure you have a C++ compiler installed (such as GCC).
Ensure your system has access to `nslookup` and `whois` commands (commonly available on Linux).
Compile the script using the following command in your terminal:
```
g++ dns_info.cpp -o dns_info
```

Run the compiled script with the following syntax:

./dns_info www.domainname.com path_to_where_you_want_to_save_results!\dns_info.txt

The output file will contain all DNS and WHOIS information for the provided domain.

Tools Required

A C++ compiler (e.g., GCC, Clang).
Access to `nslookup` and `whois` commands on your system.
A terminal or command prompt to execute the compiled binary.

Script Code


// Script code here (shortened for brevity)
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#ifdef _WIN32
#include 
#define popen _popen
#define pclose _pclose
#endif

std::string exec(const char* cmd) {
    std::array buffer;
    std::string result;
    std::unique_ptr pipe(popen(cmd, "r"), pclose);
    if (!pipe) {
        throw std::runtime_error("popen() failed!");
    }
    while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
        result += buffer.data();
    }
    return result;
}

std::vector split(const std::string& s, char delimiter) {
    std::vector tokens;
    std::string token;
    std::istringstream tokenStream(s);
    while (std::getline(tokenStream, token, delimiter)) {
        tokens.push_back(token);
    }
    return tokens;
}

void queryDNS(std::ofstream& outputFile, const std::string& url, const std::string& dnsServer) {
    std::string dnsTypes[] = {"A", "AAAA", "MX", "TXT", "NS", "SOA", "CNAME", "PTR"};
    for (const auto& type : dnsTypes) {
        outputFile << "DNS " << type << " Records:" << std::endl;
        std::string result = exec(("nslookup -type=" + type + " " + url + " " + dnsServer).c_str());
        outputFile << result << std::endl;

        // Interpret specific records
        if (type == "MX") {
            outputFile << "Interpretation: These are mail exchange servers for " << url << std::endl;
        } else if (type == "TXT") {
            if (result.find("v=spf1") != std::string::npos) {
                outputFile << "Interpretation: SPF record found. This specifies which IP addresses are allowed to send email for this domain." << std::endl;
            }
        } else if (type == "SOA") {
            outputFile << "Interpretation: This is the Start of Authority record, containing administrative information about the zone." << std::endl;
        }
        outputFile << std::endl;
    }
}

int main(int argc, char* argv[]) {
    if (argc != 3) {
        std::cerr << "Usage: " << argv[0] << "  " << std::endl;
        return 1;
    }

    std::string url = argv[1];
    std::string filePath = argv[2];

    std::ofstream outputFile(filePath);
    if (!outputFile.is_open()) {
        std::cerr << "Failed to create output file at: " << filePath << std::endl;
        return 1;
    }

    // Query to multiple DNS servers
    std::vector dnsServers = {"8.8.8.8", "1.1.1.1", "9.9.9.9"};
    for (const auto& server : dnsServers) {
        outputFile << "Results from DNS server " << server << ":" << std::endl;
        queryDNS(outputFile, url, server);
        outputFile << std::endl << "--------------------------------" << std::endl << std::endl;
    }

    // Attempt to get WHOIS information
    outputFile << "WHOIS Information:" << std::endl;
    outputFile << exec(("whois " + url).c_str()) << std::endl;

    outputFile.close();
    std::cout << "DNS and domain information saved to " << filePath << std::endl;
    return 0;
}

Download Script

Xidruk

Author and Developer of DNS Fetcher tool