Massdns

High-performance DNS resolver for bulk lookups

Recon & OSINT7 commands

#dns#resolver#high-performance#bulk

Installation

1Clone the repository

2Navigate into the directory

3Compile with make

4Verify installation

git clone https://github.com/blechschmidt/massdns.git
cd massdns
make

# Verify
./bin/massdns --help

Basic Usage

Massdns resolves thousands of domain names per second using asynchronous DNS queries

# Bulk resolve A records
./bin/massdns -r resolvers.txt -t A -w results.txt domains.txt

# Resolve AAAA records
./bin/massdns -r resolvers.txt -t AAAA -w results.txt domains.txt

# Reduce noise via output filter
./bin/massdns -r resolvers.txt -t A -o S -w results.txt domains.txt

# Use custom socket count for speed
./bin/massdns -r resolvers.txt -t A -w results.txt domains.txt -s 10000

Command Reference

7 commands

1Resolvers file (one IP per line)

-r

2DNS record type (A, AAAA, CNAME, MX, etc.)

-t

3Output file path

-w

4Number of concurrent sockets (default: 1000)

-s

5Output format (S=simplified, F=full, J=JSON)

-o

6Quiet mode

-q

7Use sticky sockets (faster)

--sticky

When to Use

Bulk DNS resolution of millions of domains

Performance-critical resolution tasks

Processing large subdomain wordlists

Research and large-scale scanning

Notes & Tips

Extremely fast — capable of millions of queries per minute

Use with high-quality resolvers for accuracy

Can overwhelm DNS servers — use responsibly

Output is in a custom format by default; use -o J for JSON

Common Errors & Solutions

Too many sockets error

Reduce -s value or increase system limits: ulimit -n 65536

No valid resolvers found

Provide a resolvers list with working DNS servers; check format (one IP per line)

# Bulk resolve A records ./bin/massdns -r resolvers.txt -t A -w results.txt domains.txt # Resolve AAAA records ./bin/massdns -r resolvers.txt -t AAAA -w results.txt domains.txt # Reduce noise via output filter ./bin/massdns -r resolvers.txt -t A -o S -w results.txt domains.txt # Use custom socket count for speed ./bin/massdns -r resolvers.txt -t A -w results.txt domains.txt -s 10000