Wieeeeerd thing with my map

well, as every map editor does, i test my map every so often. When i play on my map, sometimes people can join. These people are not local (positive) and i do not own a server. So then, i am playing with a whole bunch of people. Verrrrry strange... but pretty cool. Is there any idea about why that is happening?

Dono, but happend to me once when I had a map that was like 5% complete . Check the name of your map to see if its used or not, I think people might be mistakeing it for something else.

When you start a game by using the "create server" option, that's exactly what your pc becomes; a game server. I'd have thought that your firewall would have stopped anyone connecting though, unless you set it up to allow them, but then you'd already have known why they could join your map.

I absolutely shit myself one time, when some guy joined a small map I was testing without me noticing him. I turned around to run to where the tripmines were, and this dude is running at me with all guns blazing. My little map, the small corner of the universe where I knew there could be no other thing, and behold, there was some other thing, and it's name was death, and it was coming for me. I don't think I'd have got any more of a fright if it happened for real in the street.

typing sv_lan 1 in the console should stop random internetz people connecting.

The thing I don't get is how they download your map...

It's something like sv_allowupload or sv_allowdownload. Again, a server variable that defaults at 1.

Just turn off your internet before you run the map. And what kind of map is it? TF2, HL2, Gmod? If it's Gmod then they automatically download the map, just like a TF2 map.

You probably have steam port forwarded or you're not using a router.