Put the summary of the bug you're having here

What I expected to happen was...:
I expected to be able to run a vanilla 1.7.2 server as I have run other vanilla servers in the past. I expected my friends to be able to connect and play.

What actually happened was...:
I was able to connect to the server from a local computer, but if I tried to connect over the internet the server would crash nearly immediately. This is despite running a heavily modded 1.6.2 server for a long time with no problems and multiple players.

I now have a message that pops up when I first load the 1.7.2 server jar:
INFO: Your platform does not provide complete low-level API for accessing direct buffers reliably. Unless explicitly requested, heap buffer will always be preferred to avoid potential system unstability.

This didn't appear previously. The error log that appears in the server folder suggests resolutions, but previously there were no issues at all so I wonder if there is some other reason.

Other people having similar issues can be found in this thread:
http://www.minecraftforum.net/topic/2064051-linuxserver-172-process-ended-internal-exception/

Steps to Reproduce:
1. Run a 1.7.2 vanilla server on a 32 bit Debian 7 machine
2. Connect to the server over the internet
3. Run around a bit; particularly trying to fight zombies and interact with doors and buttons seems to cause the crash.