so I'm turning red rocket into a settlement with walls and the big junk fence gate. In Sanctuary the npc's open and close it, will the raiders do the same? do I need to place more guns by the gate?

Raiders seem to just spawn within the settlement in some cases at least in Sanctuary.

Spots I haven't seen spawns in Sanctuary are pretty much the Sole Survivors House and the house with the workbench...So plan around those and you can be satisfied that you walled off your community.

Check mine in my Sig, never had a spawn inside although I'm not saying it's impossible. The settlers always leave the bloody door open though so if anything did make it past the turrets then I'm sure it'll find it's way in.

At the drive-in attackers seem to spawn outside to the east, at least this far in my game. I haven't bothered with doors, as they are left open all the time. I usually just fence in the open areas and lead the raiders towards entrances guarded by lots of turrets.

WOW Curly, that's one hell of a base!! I'm inspired! which screen recording software did you use?

Are settlement gates automatically closed by settlers during an attack? Whenever I'm there, they're forever open.

they're forever open, because a settler or companion only has to be within close proximity (like, for instance, a guard at a nearby tower) and the gates swing open.

And the bad guys will walk through them.

It's bloody ridiculous.

Not surprised by this. You'd have hoped Bethesda would have realise players will put gaurdposts next to their junkyard gates. Am now tempted to replace all settlement gates with a single doorway and train integral guns on it. You might need two doorways in and out, as you know that damb trader's cow will glitch in one of them. Well at least it keeps the beast off the roof - for change.

I made a laberinth around my settlement, they need to go all the way around the wall to get to the stares which leads to a door to the inner wall than need to go all the way around to go back down stares and go back all the way to the first floor door with turrets at intrivial points throughout the laberanth and 2 watching the doors and stares.

Spawned in 5 legendary raiders and legendary gouls to test it, nothing is getting in there unless it spawns inside.