DNS Online Filter

Decides if provided domains are safe based on DNS threat blocking providers intelligence.

Blocklists are not required. Instead, it makes use of the following public DNS resolvers:

• Quad9 (9.9.9.9, 149.112.112.112)
• Strongarm (54.174.40.213, 52.3.100.184)
• SafeDNS (195.46.39.39, 195.46.39.40)
• ComodoSecure (8.26.56.26, 8.20.247.20)
• NortonConnectSafe (199.85.126.30, 199.85.127.30)

in parallel to verify if the domain is safe.

If a provider returns either NXDOMAIN, NODATA or a sinkholed IP address for a specified domain, it will end other queries and return False (domain unsafe).

If all providers correctly resolve the domain, it will be considered safe.

You can add as many threat blocking DNS providers as you want to the script. The 5 providers were chosen to demonstrate the proof of concept.

Setup

Requires Python 3.6.

Python packages

• dnspython
• asyncio
• pyasn

IP to ASN database

You also need to provide an IP to ASN database for pyasn.

I strongly suggest that you update the database with the following scripts

Usage

async-filter.py domains.txt

Output

[root@localhost]# python3.6 async-filter.py domains.txt 
google.com --> safe
cnn.com --> safe
stat-dns.com --> unsafe, filtered by NortonConnectSafe
www.zonemach.com --> unsafe, filtered by Strongarm
www.yasli-sad.ru --> unsafe, filtered by Strongarm
www.vinhosportimao.com --> unsafe, filtered by Strongarm
www.unblocking-acccount.000webhostapp.com --> unsafe, filtered by Strongarm
www.thephonecompany.com --> unsafe, filtered by Quad9
www.softica.fr --> unsafe, filtered by Quad9
www.siginlocalecountry.com --> unsafe, filtered by Strongarm
www.shoko-bussan.sakura.ne.jp --> unsafe, filtered by Quad9
www.secure17.000webhostapp.com --> unsafe, filtered by Strongarm
www.rixrax.com --> unsafe, filtered by Strongarm
www.residentstudents.org --> unsafe, filtered by Strongarm
www.registery-fanpages45.gq --> unsafe, filtered by Quad9
www.regiojardines.com --> unsafe, filtered by Strongarm
www.psicl.000webhostapp.com --> unsafe, filtered by Strongarm
www.prorammexico.com --> unsafe, filtered by Strongarm
-------------RESULT-------------
2/18 Safe
16/18 Blocked
Total time: 9.669567823410034

domains.txt

The list of domains to lookup. Must be one per line.