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DNSGen vs MassDNS: catalog facts
DNSGen	MassDNS
Best for: Security testers preparing authorized subdomain discovery	Best for: Administrators and security testers resolving large domain lists on networks they are authorized to assess
Free Free and open source under the MIT license.	Free Free and open source under GPL-3.0.
Command line	Windows, Linux, Command line
Generates domain variations using multiple permutation techniques Accepts custom wordlists All 3 strengths for DNSGen Generates domain variations using multiple permutation techniques Accepts custom wordlists Includes patterns for cloud providers and service names	Handles bulk DNS lookups Reads resolver lists and domain names from files All 3 strengths for MassDNS Handles bulk DNS lookups Reads resolver lists and domain names from files Outputs DNS responses for later filtering
Requires input domain names to generate permutations.	Intended for authorized DNS reconnaissance and testing
Downloadable app	Downloadable app
Open source	Open source
License: MIT	License: GPL-3.0
Not stated if an account is needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Sources for DNSGen github.com/AlephNullSK/dnsgen Catalog checked October 8, 2026	Official website Full listing and sources Sources for MassDNS github.com/blechschmidt/massdns Catalog checked October 8, 2026

“Not stated” means we have not confirmed it. Features can vary by device and plan.