If you are running OS X Server there are likely many services that you don't need that start by default anyway. If you use a firewall like Little Snitch these will generate alerts that can derail other services.
An example of one common such alert is:
gamed wants to connect to static.gc.apple on TCP port 443 (https)
This particular alert involves the Game Center service. It is something you almost certainly don't need on a server, but it will keep trying to connect and generate these alerts anyway.
1. Open terminal and paste the following line at the prompt:
launchctl unload -w /System/Library/LaunchAgents/com.apple.gamed.plist
That should do it. If you don't get any feedback it probably worked. If it you get an error message it didn't.
If you want to test and be sure there are a couple of things you can do.
1. Paste the same line again. It should now return this:
/System/Library/LaunchAgents/com.apple.gamed.plist: Could not find specified service
2. Launch one of the default OS X games like Chess. The system should then try and initiate several gamed connections; if you don't see them it means that this process has been disabled. This does assume that there are no Little Snitch rules (temporary or permanent) either allowing or allowing access to the gamed process. To be sure open Little Snitch > Rules..., click on "all rules" on the left then enter "gamed" in the search box on the right. If you see gamed in the column on the right select and delete those rules, then try quitting and opening the Chess application instead.
If you wish to undo this then simply paste the following line into terminal:
launchctl load -w /System/Library/LaunchAgents/com.apple.gamed.plist
This should have the exact opposite effect. Unless you get an error message it was likely successful. Again, if it works, there is no feedback.
If you want to test and be sure there are a couple of things you can do.
1. Paste the same line again. It should now return this:
/System/Library/LaunchAgents/com.apple.gamed.plist: service already loaded
2. Launch one of the default OS X games like Chess. The system should then try and initiate several gamed connections; if you see them it means that you have successfully reenabled the process. Again this assumes that there are no Little Snitch rules related to the gamed process in place; if there are please delete as described above and quit/reopen the chess application. .
There is a more complete list of commands for disabling various services (and a discussion of the implications) here:
http://forum.kodi.tv/showthread.php?tid=217607
This is primarily about kodi but there are some good tips in there.
A few other processes that can likely be safely disabled (and re-enabled if needed) in OS X Server include....
Calendar
launchctl unload -w /System/Library/LaunchAgents/com.apple.com.apple.CalendarAgent.plist
launchctl unload -w /System/Library/LaunchAgents/com.apple.CalendarAgentLauncher.plist
launchctl load -w /System/Library/LaunchAgents/com.apple.com.apple.CalendarAgent.plist
launchctl load -w /System/Library/LaunchAgents/com.apple.CalendarAgentLauncher.plist
Address Book
launchctl unload -w /System/Library/LaunchAgents/com.apple.AddressBook.SourceSync.plist
launchctl unload -w /System/Library/LaunchAgents/com.apple.AddressBook.AssistantService.plist
launchctl load -w /System/Library/LaunchAgents/com.apple.AddressBook.SourceSync.plist
launchctl load -w /System/Library/LaunchAgents/com.apple.AddressBook.AssistantService.plist
iChat
launchctl unload -w /System/Library/LaunchAgents/com.apple.soagent.plist
launchctl load -w /System/Library/LaunchAgents/com.apple.soagent.plist
Airplay
launchctl unload -w /System/Library/LaunchAgents/com.apple.AirPlayUIAgent.plist
launchctl load -w /System/Library/LaunchAgents/com.apple.AirPlayUIAgent.plist
This post also mentions com.apple.blued.plist, which would disable bluetooth. This is something that can (unlike the other processes mentioned) also be done through the GUI (System Preferences... > Bluetooth).
This article looks at how you can research active process and delete as needed. It is a great primer on finding and researching active services.
https://vilimpoc.org/blog/2014/01/15/provisioning-os-x-and-disabling-unnecessary-services/