Re: Discovering Live Hosts

["rajat swarup" <rajats@gmail.com>]

On 8/7/07, Nikhil Wagholikar <visitnikhil@gmail.com> wrote:
>
>
> Can anyone kindly guide me, as to how to find live IP Addresses from a
> given Pool of IP Addresses (Range of IP Addresses) with as less false
> positive results as possible and as quickly as possible? Is there any
> tool out (no matter shareware or freeware), which focuses on finding
> live IP Addresses from Pool of IP Addresses?
>
Hi Nikhil,
I would choose some 40-50 odd most commonly used ports and perform a
SYN Stealth scan only on those ports -sS -P0 (e.g.,
21,22,23,25,53,80,443,3389,9000 etc).
I'd also do a ping scan.
Now there are 4 possibiities:
1. A host responds to ping
2. A host responds with open port
3. A host responds with a closed port
4. A host resolved DNS name
In each of the four cases you come to know the host is alive.

HTH,
Rajat.
-- 
Rajat Swarup

http://rajatswarup.blogspot.com/

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