This is for the people who are always getting raided by others in faction servers here out some of the ways you can defend.

1.checkers
make holes that are 3 deep and make them in a checkerd pattern, when the enemy is running along them to get to you try to shoot them with a arrow and that will make them fall down the pit or they may just accedently fall down it also fill the bottom part with lava (you don't have to though)

2. lava walls
put lava on the outside of you walls and this will make it very hard for the enemy to get close to your base. Make sure the lava goes all around your base so they can't get close to it.

3.obsidien walls
This will make it so if the enemy makes TNT cannons it wont effect the wall and the they wont be able to get inside your base.

4.hall way
.make a long hall way with a iron door at the end and have a swich to the side of it. If the enemy gets into your base (mayby with ender pearl) run down this hall way and make sure the enemy is chasing you. when you get to the iron door wait untill they are close and then flick the swich it will close the door and you should then put some stickey pistons outside the door and make the pistons pull out and then they will fall down a pit to there death.

5.Hidden bombs
If the enemys are huddled up together or are building forts near you base this will come in handy. make several swiches and connect it with redstone and make the redstone go in random directions. When you think you have places enough redstone put some tnt at the end and this should stop them from being able to build bases for a while.(make sure you place the redstone and tnt underground or they will notis it and wont go or build there).

This is it please ask if you wan't me to post more traps to help you defend you base.