When I'm travelling in the end or fighting the dragon, I usally have a pumpkin on my head. I don't like the enderman at all
It feels like the viewing distance of the enderman to get aggro on you is quite short on this server though, I haven't been in trouble at all so far.
The water bucket, as mentioned above, can also be a lifesafer. Not only for the enderman, but also to negate fall damage, obsidianise lava, ...
The easiest way to build safely imo is to have the proper gear on you:
- diamond boots with feather falling IV and (some sort of) protection IV
- diamond leggings with (some sort of) protection IV
- elytra and rockets to fly away and prevent fall damage
- diamond helmet with (some sort of) protection IV
- diamond sword with sharpness V
- bow with infinity and power V and 1 renamed arrow
good luck with your build/fights!