Python script to lookup NS PTR with list prefixes from one AS

ns-prefix-as-lookup.py

##
# chuyenvd@vng
# 2023-09-25
##
import dns.resolver
import ipaddress

AS = "AS12345"

with open(AS) as f:
    for prefix in f.readlines():
        prefix = prefix.split('\t')
        for i in prefix: 
            ip = ipaddress.IPv4Interface(i)
            try:
                ptr_zone = ipaddress.ip_address(ip.ip).reverse_pointer
                lk_zone = ptr_zone.replace('0.', '', 1)
                ns = dns.resolver.resolve(lk_zone, 'NS')
                for i in ns.response.answer:
                    print('\x1b[6;30;42m' + 'NS found:',lk_zone + '\x1b[0m')
                    for j in i.items:
                        print('NS:',j.to_text())
            except:
                print('\033[91m' + 'NS missing:',lk_zone + '\033[0m')