Re: Nmap -PU can't find any host available

[Daniel Miller <bonsaiviking () gmail com>]

On 03/28/2014 09:45 PM, Anorpi Jia wrote:
> Hi,
> I run [nmap -sn -n -PU xxx.xxx.xxx.xxx/24]for host discovery，The
> description of -PU in official Documents:
>
> [Upon hitting a closed port on the target machine, the UDP probe should
> elicit an ICMP port unreachable packet in return. This signifies to Nmap
> that the machine is up and available.]
>
> Meaning that when the target host returns ICMP unreachable [Type3
> Code3].Nmap will report this host is available.
> I use wireshark to capture.And wireshark displays many hosts replied ICMP
> port unreachable,but the final result is shown by nmap:"Nmap done: 256 IP
> addresses (0 hosts up)"，Meaning is no host is available. Selinux and
> iptables are disable.
>
> My computer:
> Centos 6.5
> Nmap 6.40
> The Screenshot in attachments
Hello,

I cannot reproduce this result. Please provide the output of this command:

nmap -sn -n -PU -ddd X.X.X.X

where X.X.X.X is one of the hosts you expect to find up. This will give 
diagnostics of what Nmap is sending and seeing, in case there is a bug.

Dan
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