raw-dns-cli

A minimal DNS CLI tool for educational purposes. Look up DNS records from the command line with a clean table output, hex dump mode, and customizable DNS servers.

Features

• 🔍 A/AAAA/CNAME record resolution – Look up IPv4, IPv6, and alias records
• 📦 Hex dump mode (-x) – View raw DNS packets in hexadecimal format
• 🌐 Custom DNS server – specify any resolver (default: 1.1.1.1)
• 🎨 Color-coded output – Green for A records, blue for AAAA, yellow for CNAME
• 📋 Table formatting – Pretty-printed results with unicode box-drawing characters
• 🛠️ Simple CLI – dns_cli domain [dns-server-ip]

Installation

Standard

# Clone the repository
git clone https://github.com/df1gg/raw-dns-cli.git
cd raw-dns-cli

# Build with make
make

# Or compile manually
gcc -Wall -Wextra -Werror -pedantic -std=c11 -Iinclude src/*.c -o dns_cli

If you use Nix:

nix-shell
make

Usage

# Basic A record lookup
./dns_cli google.com

# With hex dump
./dns_cli -x google.com

# Custom DNS server with hex dump
./dns_cli -x google.com 8.8.8.8

# Show help
./dns_cli -h

Screenshots

Standard A record resolution for google.com

Raw DNS packet hex dump with -x flag

Usage information with -h flag

Project Structure

raw-dns-cli/
├── include/         # Header files (domain.h, network.h, table_print.h)
├── src/            # Source files (domain.c, main.c, network.c, table_print.c)
├── Makefile        # Build automation
├── .gitignore
├── shell.nix       # Nix development environment
└── README.md       # This file

Generated files (dns_cli, build/) are excluded via .gitignore.

How it works

1. Query construction (main.c + network.c): Builds a standard DNS query with the domain name encoded in wire format, transaction ID, and query type/class
2. UDP send (send_query): Sends the query via SOCK_DGRAM to the specified DNS server on port 53
3. Response parsing (parse_recv): Parses the DNS response, extracts answer records, and handles name compression pointers
4. Display (table_print): Renders results in a color-coded table with proper formatting

License

This project is licensed under the MIT License – see the LICENSE file for details.

TODO / Future improvements

• Basic A record resolution
• AAAA/CNAME record types
• Hex dump mode
• Color-coded output
• Socket timeout & retries (-t / --timeout)
• EDNS support
• TCP fallback for large responses
• Async/non-blocking I/O
• Additional record types (MX, TXT, SRV)
• JSON output option (--json)
• Reverse DNS lookup (PTR records)