Re: nmap OS detection over OpenVPN v. 2.2.1

[David Fifield <david () bamsoftware com>]

On Thu, Jan 24, 2013 at 06:07:28PM +0400, Антон Конвалюк wrote:
> I have got a virtual pentest lab (ProxMox VE). And for outside
> connection I use OpenVPN (bridged). It works fine, but there is a
> problem.
> I'm trying to nmap MS Windows 2000 machine in VE. To do it I use
> Backtrack 5 R3 connected to virtual network over VPN. But nmap cannot
> recognize remote OS.
> But if I close my VPN connection, add network interface (with IP from
> the same subnet as Backtrack 5) to MS Windows 2000 machine and nmap
> it, everything is OK.

According to the fingerprint you sent, the VPN is changing the TCP
window and MSS, which is the reason why it fails to match.

Use the --osscan-guess option whenever you just want to see the closest
matches and you don't want to see a fingerprint.

David Fifield
_______________________________________________
Sent through the dev mailing list
http://nmap.org/mailman/listinfo/dev
Archived at http://seclists.org/nmap-dev/