Aggressive Mob problems on my server

[OrgasmicRain]

This is actually the first post I have ever made on this site. So I'll get right to the point.
I made a Minecraft server for me and my friends. We made a large castle with a surrounding wall with overhangs for spiders.
The entire thing isn't all that large, but there is torches everywhere. For some reason, Creepers, and other aggressive mobs keep spawning within the walls I'm wondering why.
We have checked all around the walls and underground for dungeons. But everything is sealed off.
Wat do?

[CarrO]

make sure there is no grass / dirt in the castle

[OrgasmicRain]

[QUOTE=maxolina;31608840]make sure there is no grass / dirt in the castle[/QUOTE]
Aggressive Mobs.
Creepers, Skeletons, Spiders, and Jockeys are spawning. Not like sheep.

[lushish]

You sure there's no dark parts?

[Zero-Point]

Are there any trees within your walls? If so, they're spawning on top of them. Provide a means for illuminating tree-tops.

[TheFrisk]

Is your castle scary looking?
It's a well known fact that scary looking buildings tend to raise the spawn rates of hostile mobs.
The only solution is to destroy your castle and start over.

[7DeadlySyns]

Get Zombe's Modpack and activate the mod called "Safe" or something. It will tell you where inside your map that hostile mobs can spawn. Very useful tool.

[DireAvenger]

If the map was artificially lowered to bedrock level or near it, the mob spawn rates become drastically higher due to the depth-chance rule. If this is the case, then there's nothing to stop the mob spawns.

[Bran]

[QUOTE=DireAvenger;31616032]If the map was artificially lowered to bedrock level or near it, the mob spawn rates become drastically higher due to the depth-chance rule. If this is the case, then there's nothing to stop the mob spawns.[/QUOTE]

didn't notch remove the depth-chance rule, saying something like 'it was way too annoying'? i remember reading something like that in earlier patch notes

[Rama214]

Same problem here, the mobs are agressive in my server.

[droolingPhantasm]

[QUOTE=Rama214;31616264]Same problem here, the mobs are agressive in my server.[/QUOTE]
Even pigs and sheep? Cows, chickens too? You've done something wrong to the animal kingdom. The chickens have come up with a plan to take you down, and they won't stop until you delete the world.
RAMA214 IN:
FARM RUSH
When animals attack!