Hacker News Reader

Comment by PaulCarrack | Hacker News Reader

> Windows by default, un-firewalled, will announce its presence to a network, and in old versions, that could even be the internet at large

By announcements you are referring to broadcasts which are limited to the broadcast domain of whatever IP the ISP has assigned you. Plus those are largely blocked by the ISP beyond that.

So to say that you are broadcasting to the world that you have an SMB share available is not true. An attacker would have to scan for it (i.e. make an active connection to TCP port 445 on your machine).

View on HN

This is the correct answer. Broadcast packets do not reach outside of a network segment. The “thousands” of Windows machines OP saw were probably part of the same office network they were sitting in (where other mechanisms may actually have made more of them visible than a simple broadcast would, but intentionally).

Sitting at home connected to the Internet over a point-to-point link, you’d see zero Windows machines that are not inside your home, now and back then.

When I got my first cable modem in maybe 1995, there were about half a dozen of my neighbors computers in Network Neighborhood. Most with unprotected shares and printers. Basically everyone running Windows on my C block. It got cleaned up within a few months tho.

Pre-cable modem era, the dialup networking "adapter" in Windows 95 was bound to "File and Print Sharing". People who had both a LAN and a modem could inadvertently "share" with the Internet.

I may or may not know something about sending print jobs that said "FEED ME CHEESE" in Figlet to inadvertantly shared printers and waiting for pings to stop coming back.

I stand corrected (sort of). I did specifically say that you‘d see zero other machines when connected to the Internet over a point-to-point link, but I indeed had no idea that in the US there were cable modems from different subscribers within the same subnet/segment and without any filtering.

In Germany, as far as I can tell it was all point-to-point.

That being said, around that time, or maybe slightly later, completely unencrypted WiFi networks were also commonplace, so…

You’re lucky it was only a few months. I think it took until 1999 or 2000 for my cable isp to subnet their entire /16 so that you weren’t flooding the entire city with broadcast packets, getting random windows messaging service messages, etc.

That said, it was super nice to open Quake 3 and be able to plan LAN mode with anyone in town.

Saw something similar at the summerhouse of a friend around 2008 or 2009. Somehow the whole neighborhood was in one giant LAN with one another there, sharing a common gateway to the internet? Around 30 or some such computers of neighbors showed up. Super weird.

Cable modem systems often ran with no broadcast filtering, and pretty big netmasks. Something like a /22 wouldn't be uncommon.

A local FTTH provider in my area does shockingly little broadcast filtering. It was interesting to see how much noise traffic was out here in the "business class" subnet that my Customer's static IP was coming out of.

Reply on news.ycombinator.com