RE: Security test of firewall dose not show UDP port 500 is open

["Arley Barros Leal" <arley.leal () sonae com>]

Hi MTK,

Two possible scenarios:

1) Pix is an IPsec end-point.
   In this scenarios pix will reply only if "isakmp enable interface-name" is set.

2) Pix is forwarding isakmp UDP500 to an internal IPsec end-point.
   In this scenario behavior may vary if the forwarded system has isakmp up and running or not.

My guess is that your pix is forwarding ISAKMP to an internal host (a VPN server probably), that would explain those 
different scan results. 
Try looking on the config for a static mapping like this: 

   static (inside,outside) udp interface 500 internal_host 500 netmask 255.255.255.255 0 0

Cheers,
Arley


-----Original Message-----
From: mtk () mrc dk [mailto:mtk () mrc dk] 
Sent: segunda-feira, 27 de Março de 2006 8:45
To: pen-test () securityfocus com
Subject: Security test of firewall dose not show UDP port 500 is open

Hi all,

We have been using Nessus for security scanning the Cisco Pix firewalls we install for our custemers. I have one "old" 
repport showing ISAKMP UDM port 500 is open. The firewall isn't updated but now the port has disapeard fro the new 
rapport?
We have asked Cisco if the securiyt scanner is supposed to find UDP port 500 (I don't think so) and a CCIE from Cisco 
have told us "no the port is hidden."

I wonder how the port can be in the old repport?

If any one has any input please let me know.

Best regards,

MTK

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