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List of reverse DNS records for a subnet

Terminal - List of reverse DNS records for a subnet
nmap -R -sL 209.85.229.99/27 | awk '{if($3=="not")print"("$2") no PTR";else print$3" is "$2}' | grep '('
2009-09-02 16:33:15
User: netsaint
Functions: awk grep
4
List of reverse DNS records for a subnet

This command uses nmap to perform reverse DNS lookups on a subnet. It produces a list of IP addresses with the corresponding PTR record for a given subnet. You can enter the subnet in CDIR notation (i.e. /24 for a Class C)). You could add "--dns-servers x.x.x.x" after the "-sL" if you need the lookups to be performed on a specific DNS server.

On some installations nmap needs sudo I believe. Also I hope awk is standard on most distros.

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Terminal - Alternatives

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What others think

Looks like different version of nmap spit out different text. Just do the nmap -R -sL network and you see what comes out. Very quick and simple. The format the output the way you need...

Comment by netsaint 242 weeks and 1 day ago

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