User blog comment:NoBanana/New Milestone/@comment-24899099-20150805164542/@comment-4842859-20150821225429

NoBanana is correct. There used to be a way to obtain a user's IP address, but it was not an intentional feature and as such Roblox has patched it. Even if IP banning were still possible, it's a very flawed method and easy to bypass - anybody with a little knowledge would only be held up for a few mintutes longer than normal.