Explanation of the Issues Today [16/03]


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Hello everyone, just thought I'd make a post to clear up some confusion about what actually happened today (crashing and rollbacks)

Firstly, I'd like to point out this is the first time I've had an issue or ran into anything similar to this; which is why it took us so long to actually figure it out. Once it first started, we thought, oh, it's because of the high player count (there was 63 when it first crashed.) Then it happened again, and again, and it was on the 3rd time when we thought, this definitely not right. We took a look at our timings and to our surprise, "PacketPlayInBlockDig" was #1 with 893.45% of the tick. We were all ultimately confused.
We tried removing Luckyblocks as a test to see if they had caused it (they were directly under it taking up 353.80% of the tick) and we thought we'd solved it, which is why I put the announcement saying you can rejoin. Turns out we were wrong. We thought then, right someone has exploited by sending thousands of packets to the server to overload it. We did some snooping and finding players, to no success. We then thought right, let's check the thread dump. In there were quite a few issues regarding Mojang's servers going down at the same time, so we checked minions (they were also quite high up on timings) and disabled their skin option as they contact Mojang for the skins (incl when the Mojang servers are down). We then again thought we'd open and let people in (without an announcement), this didn't work. Crashed yet again.
Then my fellow Towny server owner joined and had thought it might be Slimefun, I explained we're using a custom jar, that was dismissed quickly. He then found a plugin to limit the number of packets a client can send to a player. We thought we'd give it a try. Boom. All is well.

After all, it turns out a player was exploiting and sending too many packets to the server causing it to overload.

What a lovely day.
Thanks for your continued support,
Luke. ?