You should engage some experts who have had their red team training and some ethical hackers to try to get into your server. This might not sound like something that you would enjoy, but you would need to do this so that any weaknesses can be found.
Once the weaknesses have been located on the server after the red team training, then you can fix them. The sooner they are fixed, then the less likelihood there is that you will suffer an actual attack from a non-ethical hacker.
