What is the best way to defend settlements?

I definitely second Kalina's wonderful answer that the best defense is using your brain, but I figure this question could use some answers with specific Fallout 4 gameplay answers. That and rudimentary military tactics will turn raids from a problem into a source of minor loot.

First, as pointed out by Kalina, all settlements have a limited number of approaches for enemies. Find them (or use your brain to figure them out), and that's where you need to put your active defenses. No sense in having turrets at the opposite end of any approach. Obviously, bridges, roads, railroads and natural breaks in the terrain tend to be your main source of enemy approaches, so you can focus on building up defenses there before finding out the hard way, if you wish. Building up unmanned defenses also has the advantage of increasing your settlement's defense value, which deters raids from happening in the first place (lowers the chances/frequency of a raid occurring), compared to undefended or lightly defended settlements.

Second, you can do what people have done since prehistory and build walls to keep out invaders. It's not usually necessary to ring an entire settlement with walls (though it is possible, and with some of the smaller settlements, even easy), but you do want to use long walls to funnel enemies towards your active defense systems. And note, I'm talking about walls, not fences. Assume the raiders will be able to jump over anything you can, which makes fences useless for defensive purposes. And on that note, the more solid walls are better for this purpose than the scrappy looking ones that have gaps and holes... because enemies can always shoot through those. (Well, sometimes. You've probably noticed that there are some problems with collision detection in the game engine). The wood shack foundation "structure" (Structures -> Wood -> Floors) makes for a really nice, tall, thick concrete wall, if you really want to give your settlements an impenetrable castle feeling, and are thick enough to mount turrets on top of to boot.

Speaking of walls, if you do try to ring an entire settlement with a wall, you will almost certainly run into the max items per settlement issue, which is indicated in-game by the "size" bar in the top right corner of the screen. You can get around this by scrapping extraneous structures and items, as well as by an exploit - if you drop any gun and then store it in your workshop, the game engine will count that as reducing the number of items in the settlement by 1. (This only seems to work with guns, not other types of items).

Third, speaking of walls and active defenses, it is generally tactically advantageous to fire from an elevated position, and this applies in Fallout 4 too. So don't build turrets on the ground, build them on an elevated position, either naturally occurring, or constructed. (You can always build temporary ladders and stairs to reach high spots.)

I will try to have my turrets either on the top of my defensive walls (by using the wood shack foundation walls, or building my defensive walls as multi-story buildings and using the roof/floor of the top level) or placing the turrets further back, atop an even higher structure. See below for an example with the Red Rocket "settlement," that I use to store my collection of possible companions. I've had a couple raids here, and each time, the super mutant raiders just ran back and forth in front of the wall while my turrets chewed them to shreds.

Fourth, you can, and probably should, arm your settlers. What else are you gonna do with the literally hundreds of pipe guns and suits of raider or leather armor you'll come across in the wasteland? "Trading" them to a settler is a good way to have a well armed population to repel anything that manages to limp through your automated defenses. (If you give them a gun, they will have unlimited ammo for it, so long as they also have at least one bullet for it in their inventory as well.)

The smallest turret gives the most bang (literally) for the buck (or components) invested in Defense. You can have wall-to-wall turrets for less than a few missile turrets.

Some people spend a lot of time and resources building walls around settlements. Three things are wrong with this approach:

• When Super Mutants can spawn within the walls, which they do, then what good are walls?

• Walls count nothing towards settler happiness. The Fallout 4 help systems specifically says to raise Defense points to increase Happiness.

• Walls count nothing towards Defense points and high Defense points are what keeps attackers away.

If, instead, you reach the goal of having 80-100 defensive points in each settlement, not only will you have few if any attackers, but you will have a ton of turrets to quickly kill the attackers.

I had surrounded the settlement with walls. It took time, but I did it. I'd left a corridor conveniently targeted with turrets and loaded with traps. I waited excitedly for the raiders to come.

And they did. A group of about 10 supermutants just spawned in the middle of the settlement! So much for the walls. They were also generously supplied with grenades, making short work my turrets (most of them were facing wrong direction anyway).

Well, tower defence strategy doesn't apply, when enemies just turn up from thin air.

FYI: I was level 22, it was Greentop Nursery.

I've only experienced one attack on Sanctuary, with only 3 Raiders.. so my experience may not be accurate for larger raids later in the game.

The basic Turret seemed fairly effective, taking down one Raider before being destroyed.. my townsfolk took care of a second enemy, and I defeated the last one. I feel like a Turret is comparable to a Settler, but can be repaired if they're taken out.

Turrets are limited by line-of-sight, but they appear have a 360-degree attack radius once they spot an enemy. I've been spreading mine out around Sanctuary, mostly along the central street.

I have yet to hear of Raiders destroying placed walls, so I feel like the most effective defense may require a wall around the entire settlement. I've considered ignoring the existing houses and constructing a multi-level tower to keep everyone safe inside, while including patches of dirt for Food Resources.

I don't know if this has been mentioned or not.. BUT, i had stored everything i own in the workbench at red rocket. This includes all my junk items, aid items and mods. The rest (all my weapons and armor and fusion cores) were stored in a tool chest just beside the workbench. I had been attacked last night by a bunch of super mutants who were seen using my workbench. I did not place defenses here as there were no settlers, no food, no water production or no power. I then got attacked immediately after by a couple raiders. One raider decided to loot 5 out of my 10 fusion cores and use 1 to activate my power armor and attack me with it. Upon killing this raider i was able to loot the armor pieces and fusion cores... but lost my power armor frame. I guess not only do you need to defend empty settlements, you cannot expect your items to be safe in any containers you leave them.

It's important to note that turrets have a defined arc for detecting enemies (you can see the turret rotating back and forth in that arc). If you have the turrets facing the wrong way, the enemy may slip by without being detected. Use walls etc to funnel them into the detection arc.

However, once a turret has spotted a target, it can track that target through 360 degrees as long as its in range of the gun. Make sure you don't have anything standing around that provides cover to the bad guys - use your walls to funnel them into approaching the turrets, but not to give them cover from the turrets.

Always put your turrets on top of a roof, wall, or bridge - out of reach of a super mutant swinging a melee weapon.

I use limited walls combined with guard towers (the taller of the two guard posts you can build), and 3-4 machineguns mounted in a tight circle on top of a pillar. Protect the crops, the generator, and the sleeping area. Put some chairs down near the sleeping area, too. It encourages off duty settlers to relax in the protected zone, rather than wander around and get ganked by sudden spawning of raiders. I give each settler a set of Road Leathers, Leather Armor, and a hat of some kind (so I can tell which settlers I have assigned to tasks etc). Settlers never run out of ammo for the gun they arrive with, so I usually use my weapon workbench to upgrade basic pipe pistols (etc) that I find, instead of scrapping them. Then I swap the modded pistol for the settler's one (making sure to keep it the same basic type, auto for auto, pipe for pipe, revolver for revolver). If I get a settler with a very good weapon, like a good rifle, I make sure that settler gets a combat helmet and better armor, and they get assigned to the guard posts instead of some random guy with a pistol.

I've never had a settlement wiped out or even seriously damaged, and attacks are pretty uncommon, if you have a Defense rating that is 50% or more greater than your combined Food+Water rating. Example: Food of 20, Water of 20, make your Defense at least 60+ and you will rarely get attacked.

The best defensive setup I've found is walls. Lots of walls. If you can funnel attackers to one or two entrances you can lay down multiple tiers of turrets to take care of them.

As for turrets, the basic turrets are ok against light raiders but against heavier attackers like death claws you'll want the bigger stuff. I've seen it take multiple minutes for basic turrets to kill a single death claw.

Also, turrets need line of sight in order to shoot so yes their placement matters a lot. Try to put them at a higher vantage point so that they can shoot at everything.

I tend to rely the most on a mix of heavy laser and shotgun turrets as I've found the splash damage of the missile turret to be extremely deadly to you as well. I also use the machinegun turret in places where it is hard to transmit power to.

The only thing i ever do for defense is turrets, missile and heavy laser. I've found that the most important thing is height, and line of sight for the turrets. As few as 3 to 6 turrets placed high enough with good line of sight can drop invaders from as far as 100, 125, 150 yards away. I've witnessed it in action. Very satisfying. :)

I'm going to have to give a differing opinion on this topic; walls are good for nothing. They don't keep enemies out, nor settlers in. All they do is add obstacles that your turrets can't shoot through. What should be done is protect what your enemies want to get to; your crops, your water, your settlers. It doesn't matter what direction your enemies come from if you protect what they want to destroy. Build a few tall bridges around your Farm area. Put a couple turrets on each bridge. Bridges are great for turrets because they are thin enough to allow 360 degree protection. Now you have turrets that can hit almost anything threatening your settlement from a long distance away. Make sure all of your bridges can see the other bridges and now you have overlapping fire that is impossible to assault. Make sure all of the bridges are close enough to each other that they can basically all shoot the same enemy at the same time. Keep in mind that this means that your protected area might be less than half of the settlement build space, and that's fine. If you are only using half the buildable space, then why try to protect it all? Let them defile the houses you don't use. Let them run amok where it doesn't matter. Your turrets will be waiting...

I have lured in and killed many deathclaws this way without firing a shot.

Also - heavy turrets are nice, but overlapping fire is much better. If you have to choose between 1 heavy turret or 2 regulars, always take the 2. But also keep in mind that only so much overlapping fire is needed. It's a balence.

Walls definitely help, i started using the wire fences which ended up too small. So i tried bridges which were really good. They have the height to compensate for the height differences in terrain when building uneven surfaces or in the water.

Sometimes it prevents an entire attack. A group of super mutants tried to suicide bomb my farm and the bridge blocked them. I fought off about 4 raids with just heavy turrets most of them carry light weapons or just 2x4s so mounted turrets are great. Death claws dont know how to climb walls.

Note complete bridge perimeters can cause flying cows. I had brahmen fall from the sky and do crazy things to get around bridge wall. Also dont build too high to get an even line, otherwise they can walk under the bridge (some gravity physics dont apply to contiguous objects)

I had a group of supers spawn in sanctuary right next to my old house all ways in to my base were covered by turrets (both mk2 & spotlights) so it seems to me that setting a perimeter around your town is just a waste of objects, I am currently redesigning it so that each building has its own defence setup this way I dont need to wory about them spawning in past my gates Also after I saved everyone from the supers they all stood around the bar I had setup so that looked cool

Id say turrets and well armed Settlers are the best, Sanctuary was attacked by about 15 raiders in two locations at the same time. 5 of them spawned inside my walls near the bridge where i have 2 laser turrets and 2 heavy machine gun turrets. I was in the middle of building up a huge sniper tower in the middle of the town, so i was able to snipe at both groups of attackers. No settlers were killed, one gun was damaged.

Walling around entire settlements are meaningless.

Enemies do not spawn inside walls.

Just they can ignore obstacles certain conditions.

If NPCs have a distance(fairly near, I assume 6~7 wall widths) from player and player does not watch them, they ignore obstacles. Enemy or not, all NPCs can do that.

I think this is some kinds of optimization algorithm. Considering the complexity of this game, I should agree it's an unavoidable choice.

I've found that different settlements require different defenses. For example: I had Graygarden get attacked about six or seven times. Each time I went there to help, and found the enemies (raiders or super mutants) always attacking in the same way - they basically attacked that little Mutfruit farm with the Mr. Handys from three different angles - some came from up the hill, some came from down the hill, and some were already in the settlement when I arrived. After the same attack happened three or four times, I figured I'd set up my defenses based on how the previous attacks went. I built a wall with turrets on elevated platforms to get the guys coming from the top of the hill, and I built a corridor on the downhill slope to funnel the attackers into a couple of shotgun turrets I had waiting. Next time round, it worked perfectly - I don't think the poor Mr. Handys got to kill anybody (as a side note - it's hilarious when Graygarden is attacked, since the raiders or whatever inside the perimeter are immediately set upon by six or seven Mr. Handys. I swear, this place didn't even need turrets). Another example is Jamaica Plain - I set up turrets there after unlocking it, facing out along possible approaches. When it was attacked, it was ghouls, and they were all inside the perimeter. Not sure if they spawned there or if there were simply too many of them for the turrets to take down. I ended up kiting about a dozen gangrenous ghouls in the concrete court in the centre of the settlement. After that was done, I reconfigured my turrets to point towards the centre of the concrete court. The next time that settlement was attacked, it was ghouls again, and all I had to do was get them to follow me into the ring of six or seven turrets facing inwards. I didn't need to fire a shot). So basically, I think to get an effective idea about what the best defense is for any given settlement, it is necessary to have that settlement attacked at least once, so that you can observe where the enemies come from.

This is my current strategy, but it hasn't been tested enough to be a sure thing.

I build my main building along an open border of the area, so it functions as a wall. Preferably in a corner. I also keep in mind natural terrain that prevents access. A good place for finding that sort of terrain is croup manor. The point of this is to limit approaches by foot to my settlement.

I use the wooden raised walkways (structures -> wood -> Miscellaneous) for raised platforms for turrets. I place turrets at any approach to the settlement. Sometimes that is too wide an area to defend, and in those cases I put limited full size walls between the turret fields of fire. The point of this is to force opponents to get within reach of one of the turret platforms.

Each turret platform is made up of three heavy machine gun turrets. You have to place them somewhat spread out to all fit on the platform.

The upside of this set up is it doesn't use too much building space. I am not sure how safe this is against missile launchers and suicide mutants.

If it turns out this is too vulnerable to area attacks as mentioned, then I'll look for longer ranged turrets, or have more platforms with wider spread turrets, so that one missile doesn't take out all the turrets at one area.

I'll probably turn up difficulty so that attacks are more frequent to test this.