Originally posted by TVMAN:

I have my settlement surrounded by walls and workbenches/torches/wards spread out to ensure mobs spawn outside the walls. As long as the mobs don't have line of sight on you, they won't aggro.* I've never had an issue with mobs attacking walls without first seeing me, and I have a large compound to defend.

*Edited to add that they won't aggro on walls themselves. If you have any other structures outside your walls, yeah they will go after them iirc.

That asnwers my question about my old save thanks, I had workshops built around them to try and keep mobs atleast a little away from the walls

edit
unfortunately it is an old save so i wont really play it anymore, but I do like to go around and admire my first base lol