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Comment by Cakez0r | Hacker News Reader

I think it's a bit more like going on to a shop and trying to open all the doors, cupboards and drawers to see which ones are locked ;)

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Isn't that the wrong analogy?

In this case, eBay is the shop, and I'm the customer. It's like walking into eBay and when I walk in I have to empty out all of my pockets and open my phone screen to show them that no one is telling me what to shop for (VNC).

No, because of the existence of client-side scripting with javascript, it's actually eBay that's running on your computer acting as the customer toward the shop that's your computer. You're right that the end effect is similar to having to empty out your pockets, but the underlying issue of why they're able to do that is a whole 'nother can of worms.

That's a bad analogy. It wrong because you can see what doors, cupboards and drawers are available for the public. Doors that are in-reach but that shouldn't be used by the public have signs like "restricted access" or "employees only". You can't do that with the internet. You can't see that a port is not available to you until you try it.

If you want to continue using that analogy, then you have to consider that everybody is blind and deaf, and checking to see what's locked is the only way to know if something is available.

Hmm, then how about going to the changing room area and trying every door instead of waiting for the guy to tell you which one to go to?

I made this edit to the post you replied to. You probably missed it:

> If you want to continue using that analogy, then you have to consider that everybody is blind and deaf, and checking to see what's locked is the only way to know if something is available.

About this:

> instead of waiting for the guy to tell you which one to go to?

How does that translate to TCP/IP? What is "the guy" representing? The way I see it, there is no guy.

The guy is you installing Steam to run on port 27036.

> That's a bad analogy. It wrong because you can see what doors, cupboards and drawers are available for the public. Doors that are in-reach but that shouldn't be used by the public have signs like "restricted access" or "employees only". You can't do that with the internet. You can't see that a port is not available to you until you try it.

But you can see what ports/doors are available. TCP doors are defined in the RFC and they are numbered 0-65535. Those are the ones available.

Port scanning still is analogous to trying all these doors and see which one are open.

Just because it is a lot of doors to choose from doesn't make it very different. That's why guests ask a host where the bathroom is.

When you visit a website, it's not very cool for that site to check which of all your TCP ports are open. It's none of their business.

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