I recently upgraded NIS 2011 to version 18.5.0.125; after this upgrade I have run a scan of internet service ports through Shield up and Symantec Security Check. In both scans all ports appear closed instead of stealth and this happened for the first time since I updated NIS. I have run other ports scan in the past but all ports were always stealth.
I have installed NIS 2011 on two computers and the problem is the same.
It happened to someone after update to version 18.5.0.125?
Hi raygold,
Are you behind a router or modem that has NAT? If so, the port scan tests can only tell you what the port configuration is for that device, and your Norton firewall cannot be seen or analyzed from the internet.
Thank you very much SendOfJive,I have installed a NAT router just last week.
I tried to disable router NAT feature and all ports appears fully stealth.
thank again 
raygold wrote:I tried to disable router NAT feature and all ports appears fully stealth.
Now that you have checked your Norton firewall, you should put the router back as it was in it's default configuration. NAT actually acts as a firewall that prevents unsolicited traffic from even getting to your computer in the first place. In addition, if the router has a firewall included, it should also be enabled. Running under the router's DMZ, if that's what you did, is actually dangerous from a security point of view (although the Norton firewall still protects you).
Take advantage of the additional security that a NAT router affords - unless you have a specific need, do not allow port scans to pass through by undoing the router's protections.