firewall or VPN concentrator ???

[jaideepjha () rediffmail com]

Recently while doing a pen test on a given IP, I found that all the ports except for 1723 (TCP scan) and 500 (UDP scan) 
were filtered. On port 1723, pptp service was found to be running and on port 500, ISAKMP was running.
It strongly pointed that a VPN server was running on that IP, but ike-scan returned negative result. Do you have any 
suggestions as to what device is using that IP?
Regards,
Jaideep

------------------------------------------------------------------------------
This List Sponsored by: Cenzic

Concerned about Web Application Security? 
Why not go with the #1 solution - Cenzic, the only one to win the Analyst's 
Choice Award from eWeek. As attacks through web applications continue to rise, 
you need to proactively protect your applications from hackers. Cenzic has the 
most comprehensive solutions to meet your application security penetration 
testing and vulnerability management needs. You have an option to go with a 
managed service (Cenzic ClickToSecure) or an enterprise software 
(Cenzic Hailstorm). Download FREE whitepaper on how a managed service can 
help you: http://www.cenzic.com/news_events/wpappsec.php 
And, now for a limited time we can do a FREE audit for you to confirm your 
results from other product. Contact us at request () cenzic com for details.
------------------------------------------------------------------------------