Was going to post this to /r/admincraft at first, but decided to post it here so more will see it.

As many of you may already know, in the latest snapshot for 1.9.3, Mojang has included a "server blacklist" in the Minecraft client. There are many implications of this, some of which are good, some of which are bad. If you're not familiar with the topic, here is a rundown of the situation:

What is going on? In case you weren't aware, Mojang's EULA (End User License Agreement) essentially forbids server owners from offering any non-cosmetic perks/bonuses to people who donate/pay money to said server. In short, Mojang doesn't like "Pay2Win" servers. This EULA has been around for quite some time, and back in 2014 you may recall that they made a blog post about server monetisation, leading to its own slew of drama.

In recent months (starting in February sometime), Mojang employees have started sending out emails to server owners who had servers that violated this EULA.

Very recently (past ~3 days or so), it was discovered that Minecraft 1.9.3 pre-2 had code that included a server blacklist, effectively preventing vanilla (or possibly all?) minecraft clients from connecting to specific servers. Naturally, server owners are outraged over this, particularly those that are themselves running P2W servers, who are now looking at losing virtually all traffic (and thus revenue) to their servers.

Whoa, what? A server blacklist?

Yup. In Minecraft 1.9.3 pre-2, a server blacklist was introduced in the client which connects to Mojang's session servers to fetch a .txt file full of SHA-1 hashed domain names/IPs to see if the domain/IP you are attempting to connect to (or even ping?) matches any of these. At the moment there are only 31 servers/domains on this list, 28 of which are known.

If the client attempts to connect to a server that is on the blacklist, it will silently fail, emulating a "network uneachable" error, meaning that most people will not be able to even tell that the server is blacklisted.

You can check to see if a server/domain is on Mojang's blacklist here.

If you're a server owner and you own a server owner that could potentially be EULA non-compliant, you should be concerned. It's almost certain this blacklist will only continue to grow, and there are reports from some server owners that you may not even be emailed by Mojang before you are put on the blacklist (only one known instance of this, not sure of details).

What can I do if I'm on the blacklist, or worried about it?

md_5 has covered this in his post on the matter. If looking into arbitration doesn't work or you're looking for some more immediate answers, look into contacting the people on Mojang's Brand Enforcement or Support team, or sending them an email at enforcement@mojang.com.

The Videogame Attorney of reddit fame has also started a reddit thread about this issue, you may ask him questions here.

What shouldn't I do?

Don't flame/harass/dox/DDoS Mojang or any of its employees- you're not going to help, and if anything you're making the situation worse.

Why does any of this matter? It's those servers' faults for violating the EULA!

You know, maybe you're right. I'm not going to bother defending servers who violate the EULA. Mojang does have a right to take action against them, seeing as it's their game, and they are within reason punishing those who violate their EULA.

What I have a problem with, though, is their method of doing it.

Regardless of your opinion on the matter, you must admit that Mojang has kept pretty quiet about this situation. To my knowledge, no Mojang employee has posted anything about this on social media or made any attempt to communicate to players what was going on. Mojang now has the power to silently prevent you from connecting to servers which they deem to be violating their EULA. You won't even know the server you tried connecting to was blacklisted. You may just assume the server is down and not really know what happened otherwise. This is unacceptable, in my opinion. Players have the right to know, at the very least, when they attempt to connect to a server that is blacklisted. They deserve to know that servers are blacklisted by Mojang now.

If any of you reading this care about this topic at all, I ask that you demand Mojang provide the community with some transparency for once on this controversial issue. Everyone deserves to know what's going on, not just the server admins that are effected by it.

I've seen reddit's opinion on this subject already… So I know I'm going to get some hate for my opinion on this. All I am really asking for is some transparency from Mojang, though. Perhaps a blog post on the matter. This is a pretty big deal, and people have a right to know what's going on.

TL;DR: Mojang is (finally) cracking down on servers that violate the EULA, but are their methods really all that sound…? That's a matter of opinion, but regardless I think they owe us a bit of transparency on the matter.