I’m in an environment with a lot of computers that haven’t been
properly inventoried. Basically, no one knows which IP goes with which
mac address and which hostname. So I wrote the following:
This script goes down the entire IP range and attempts to
retrieve the Hostname and mac address and outputs them
into a file. Yay!
require “socket”
TwoOctets = “10.26”
def computer_exists?(computerip)
system(“ping -c 1 -W 1 #{computerip}”)
end
def append_to_file(line)
file = File.open(“output.txt”, “a”)
file.puts(line)
file.close
end
def getInfo(current_ip)
begin
if computer_exists?(current_ip)
arp_output = arp -v #{current_ip}
mac_addr = arp_output.to_s.match(/…:…:…:…:…:…/)
host_name = Socket.gethostbyname(current_ip)
append_to_file("#{host_name[0]} - #{current_ip} - #{mac_addr}\n")
end
rescue SocketError => mySocketError
append_to_file(“unknown - #{current_ip} - #{mac_addr}”)
end
end
(6…8).each do |i|
case i
when 6
for j in (1…190)
current_ip = “#{TwoOctets}.#{i}.#{j}”
getInfo(current_ip)
end
when 7
for j in (1…255)
current_ip = “#{TwoOctets}.#{i}.#{j}”
getInfo(current_ip)
end
when 8
for j in (1…52)
current_ip = “#{TwoOctets}.#{i}.#{j}”
getInfo(current_ip)
end
end
end
Everything works except it does not find a Reverse DNS.
Sample output that I’m getting is this:
10.26.6.12 - 10.26.6.12 - 00:11:11:9B:13:9F
10.26.6.17 - 10.26.6.17 - 08:00:69:9A:97:C3
10.26.6.18 - 10.26.6.18 - 08:00:69:93:2C:E2
If I do nslookup 10.26.6.12 then I get the correct reverse DNS so
that shows that my machine is seeing the dns server.
I have tried Socket.gethostbyname, gethostbyaddr, but it doesn’t work :
(
Any guidance will be much appreciated. Thanks!