On 21/05/13 11:29, steve-alug@hst.me.uk wrote:
Every now and again, I use Shields UP! at grc.com to check that there's unexpectedly open ports on my system. I checked last night and I found 2 open ports, 5 closed ports and all the rest were "stealth" ports. The 2 open ports I was expecting. Stealth ports mean simply that they don't reply in any shape or form to the outside world. I expect, and usually get, all my ports except for the two open ones to appear as "stealthy".
I don't understand why I'm now getting 5 closed ports showing up.
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I don't forward any port ranges. I don't have a DMZ. UPnP is disabled.
The ports that are appearing as closed are: 135, 137, 138, 139, 445
Solved. It's my ISP. They started blocking these ports for everyone. So rather than them getting to my router and being ignored, and thus showing up as "stealth mode" on GRC's port scan, the ISP causes them to be explicitly blocked somewhere - thus they show up as "closed" ports on GRC's port scan.
My mind is put at rest - it's not a misconfiguration on my part! Phew.
Steve