Minecraft Blocklist Checker
Check if a Minecraft server address is blocked by Mojang. Blocked addresses cannot be joined from the Java Edition client.
How It Works
Mojang publishes the blocklist at sessionserver.mojang.com/blockedservers as a list of SHA-1 hashes. The Java client hashes the address you type, plus wildcard forms (*.example.com, *.com) and IP ranges (1.2.3.*, 1.2.*, 1.*), and compares them against the list. We mirror the list hourly and repeat those same steps.
Frequently Asked Questions
It is an official list of blocked server addresses maintained by Mojang. It is published as SHA-1 hashes so the blocked domains are not publicly readable.
The Java Edition client refuses to connect to the blocked address. Players cannot join the server directly from the client while the block is active.
Mojang updates the list on their side at irregular intervals. We refresh our mirror every hour, so results are at most about an hour behind the official list.
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