First off, there is no realistic way to limit an FTL drive because there is no such thing as a realistic FTL drive in the first place. That is to say, any drive that allows you to physically move faster than light is not only impossible but nonsense. This is due to a few reasons such as time dilation, space contraction, and energy expenditure.

What you *could* do is arrive at a destination faster than light would, by taking a shortcut. This is the principle behind many of the more **"** realistic **"** interstellar drives. That shortcut may be another dimension (hyperdrives), bending space to make distances shorter (warpdrives) or opening a hole in space to your destination (jumpdrives). All of these have the added bonus that they do not turn your spacecraft into a relativistic apocalypse bullet.

Now onto methods to limit these drives to "safe zones":

* **Limit through accuracy** - let's say that your drive is extremely inaccurate, that is to say, that if you aim at a star, you may end up *in* said star or you may end up in the fringes of that star system. Given how vast space is, it's fair to say that the chance of accurately delivering a missile to its target is less than slim. The main disadvantage of said drive is its inherent danger, so to do regular trips you'll have to aim far from your actual target lest you want to end up inside it.

* **Limit through resources** - make the drive need a special resource to work, some kind of exotic energy only found near stars. This resource would be needed not only to start the jump but to end it, so people can only jump from stars to stars. This can be expanded if you are using warpdrives or hyperdrives, so that you can only travel through "paths" of this energy. This would allow you to fine-tune how you want your spaceships to function and where you want them to go. While I say resource, this can be anything: gravity, plasma, dark matter, exotic hyper-matter, etc.

* **Limit through infrastructure** - make your drives function with gates or portals. You can set it up to work such that you can only jump from gates, to gates or both. The main disadvantage of this method is colonization and exploration. Since you'd need a gate to whatever destination you want to go to, you'd need to physically move such gates to every new system you discover. Alternatively, make it so an ancient civilization did all that hard work already and you just discovered the gates (like Mass Effect).

* **Limit through countermeasures** - set up "jump inhibitors" near important locations. These inhibitors would limit jump/warp activity in an area near them, like the other methods, they could prevent jumps from, to or both. A network of these inhibitors in a star system would prevent rogue jumps to undesired locations and, depending on the size of the devices, you may implement them in spacecraft to prevent enemies from escaping or from surprising your troops.