I was wondering if there are any access restrictions built into Forge / FML that would throw anything similar to a SecurityException. If I wanted to connect to an external resource on a remote port by opening a new socket would Forge stop me?

What exactly are you doing?

Looking to build a small monitoring tool that would send heartbeats from the server to a small application for logging. My idea what to make a small mod that started up with the server and opened a connection the server on the loopback address of the server. Like I said just a simple monitoring application nothing more nothing less.

Nopt sure if i should trust you

Have you already looked at Open Eye? It is on github. (called OpenData)

The only reason I am looking into a way to use forge in my concept is so I can make it part of the server. But since I am wanting to send pings to a destination other than the minecraft server or the minecraft client the only way I can think to do so is to open a network socket on the localhost for communication. Most of the other code will sit on it own thread to try and not interfere with the game as much as possible.

 

In essence the idea would be no more dangerous than the update checkers that come with numerous mods. The would just sends a pong when the outside app sends a ping.

Take a look at the automatic crash-reporting feature of the Minecraft Comes Alive mod. I peeked at it the other day and I think it's basically what you're trying to do (for other purposes)