VoxeLibre (formerly Mineclone 2) supports this. The server has the option for "Peaceful mode" which does what you describe within the VoxeLibre options.
Note that the setting is within the VoxeLibre options (and not the Minetest options). :)
Minetest is an infinite-world block sandbox game and a game engine, inspired by Infiniminer, Minecraft and the like.
The community is about the great and open source sandbox game writed in Lua, Minetest.
Feel free to call players for a multiplayer game or publish your project of a mod and everthing related.
Download the game. Check out the wiki.
VoxeLibre (formerly Mineclone 2) supports this. The server has the option for "Peaceful mode" which does what you describe within the VoxeLibre options.
Note that the setting is within the VoxeLibre options (and not the Minetest options). :)
Maybe MineClone has that since Minecraft has a "peaceful" difficulty setting without monsters
You can uncheck 'Enable Damage' on the start screen and the monsters will still be present, but unable to harm players. (This is what I do for playing with my kids.)
Also, MineGame/default doesn't come with any monsters. If you build up hand selected mods from MineGame, you can skip any that include monsters and end up with a full features, but monster free, MineCraft clone.