GRC san - port 80 OPEN when using a proxy server

Hi all,

new to Comodo firewall (:WAV) - had enough of Zone alarm… (:SAD) …after 5 years…

The only thing I notice is - IF I use firefox with a defined proxy server - GRC shields up notices port 80 OPEN and 113 closed ( I have 113 port forwarded on my router to a non existent IP!)
IF I set the proxy server settings to AUTOMATIC or none - these are both stealth…

this was not something I saw in Zone alarm - I CAN live with NOT using a proxy server I guess - but prefer not to - Can I stealth these ports AND keep my proxy server going?

FYI - win xp pro, Netgear WGR 614 router

Thanks a lot!


Welcome tack.

I’m a little curious here. You say your running a port check (Shields up) using a proxy? If the proxy is non-transparent, then the check will be against the proxy server and not your PC.

Also, Shields Up will check your router ports and not your software firewall.

What kind of proxy are you using?

Hi Toggie
I am using an outgoing Proxy supplied by my isp - essentially a cache for frequently accessed sites. I assume it is transparent to incoming data… (as I mentioned when using Zone alarm - no problems)
As far as the router is concerned, I understand exactly what you mean. As GRC “sees” port 80 as OPEN (when using the proxy server) I assume that there must have been a request from my PC that opened a potential port for incoming connections …there for this is passed back to my computer by the router… What I don’t understand is why 113 is seen at all - as it is effectively DUMPED by the router to a non existent machine in my network. I realise that I am essentially testing my router - APART from open ports that my computer has requested.

SO I guess i am really wondering why I have port 80 open NOW when with zone alarm I didn’t? No other parameters changed apart for uninstalling ZA and installing CPF. (:KWL)

This is NOT a big issue - just after some education (:NRD)



Just out of interest, will you try PCFlank and see what results you get.


Fascinating - before I do that toggie - I tried something else…
I Have 2 computers on the router - one has ZA one has CPF.
AT GRC, the one with ZA has the CORRECT IP, whilst the one with CPF shows the PROXY servers ip!
Remember they are both going through the same router! It looks like the OPEN port that is being reported is indeed on the proxy server - somehow, the machine with ZA is getting the correct IP to grc…confirming the system is secure…

Figure that one out! lol
As far as PCflank goes…
on the CPF machine - can not determine your ip

ZA machine:- Can not determine your IP address

Summary -

  1. am effectively in “stealth” with cpf and ZA (FWIW)
  2. ZA ensures “correct” ip is tested by grc
  3. CPF seems to make the proxy IP tested
  4. and for good measure detects a proxy server and correct ip with either firewall

We live and learn… (:LGH)



The simple thing to do is try each firewall without a proxy…

Yep - did that already ;D
GRC shows full stealth, but PCFlank says that port 80 is “visible” assumedly closed…?

Over all happy with the results and happy I can use a proxy server without compromising firewall integrity…

Although I do wonder that GRC can’t see port 80 and PCFlank can…

Thanks for all your comments


I had a problem with PCFlank before and later figured out that I had to update my IE6 settings to refresh its cache on every site visit to get accurate results.