Can a company legally block access to their public servers for a specific program?
<p>There are numerous modded Minecraft "launchers". For example: <a href="https://www.technicpack.net" rel="nofollow noreferrer">https://www.technicpack.net</a>, <a href="https://www.atlauncher.com" rel="nofollow noreferrer">https://www.atlauncher.com</a>, <a href="https://www.feed-the-beast.com" rel="nofollow noreferrer">https://www.feed-the-beast.com</a></p>

<p>All of these launchers contain modded content for <a href="https://minecraft.net/" rel="nofollow noreferrer">Minecraft</a>, which is a proprietary game owned by <a href="https://www.mojang.com/" rel="nofollow noreferrer">Mojang</a>. They circumvent the copyright and license by never actually distributing any part of the game themselves, but having the launcher (which is on the players computer) download the original files from the official source.</p>

<p>Could Minecraft modify their license to explicitly deny the use of their game through modded launchers such as these?</p>

<p>Practically, there is no maintainable way to enforce this. It's impossible to filter requests coming from a specific client unless the client reveals something which that would prompt the server to do so.</p>

<p>Legally however, is this enforceable? Can a company such as Mojang change their license and immediately make all this existing software illegal? What if these launchers published the open sourced code for their applications and a regular player compiles it and uses it to download Minecraft. Would that violate the license?</p>

<p>Technically all these launchers are doing is acting as an extremely specialized web browser for the user to download the game from its official source. I feel like it would be the equivalent of Mojang saying <em>"You're not allowed to download our game with Google Chrome from now on!"</em>, and also making no changes to their website to prevent that.</p>

<p>Mojang is a private company that can do whatever it wants with its products. You (and anyone else) as a user of their products, must abide by Mojang's directions in the use of their products, or Mojang reserves the right to not allow you to use their services or products. This includes modifications to what they see as their desired use of the products and/or customizations of their products, including methods to to circumvent Mojang's safeguards to how they want their products used by users and third parties.</p>

<p>All users of Mojang's product(s) agree to the EULA <a href="https://account.mojang.com/documents/minecraft_eula" rel="nofollow noreferrer">https://account.mojang.com/documents/minecraft_eula</a> to use the products and services in a certain way, and Mojang reserves the right to prevent users who do not follow the EULA from using their products and services. Preventing people from using the products could take the form of blocking downloads or changing the way their products operate to prevent launchers or other mods from working.</p>

<p>In the EULA, Mojang reserves the right to change the EULA at any time, so when they detect new uses of their products that they don't agree with or impact their products or other users of their products, they can change the EULA to address those situations.</p>

<p>Mojang has a right to prevent users from using their products and services in certain ways. You, as a user, have the right to stop using Mojang's products and services.</p>

<p><em>(Caveat: various laws regarding EULA enforceability and other laws may differ, depending on the user's location in relation to Mojang's location.)</em></p>

copyright internet software licensing