computer name changed automatically

Here is a good explanation http://www.reddit.com/r/osx/comments/2hxhp9/yosemite_computer_name_changing_for_ some_reason/

"There is a problem with Yosemite's mDNS sleep proxy functionality. A sleep proxy if you're unfamiliar with it advertises network services on your machine while it is asleep and if another machines attempts to connect to one of those services, wakes your machine up. In short Yosemite registers with the sleep proxy when it goes to sleep and then when it wakes up, rather than reclaiming the services sometimes gets in a fight with itself leading to the name conflict and subsequent renaming of services ("Service" becomes "Service 2", etc) and so on.

In terms of work arounds, all you can do is remove sleep proxy services from the network which is likely to be annoying as that means removing Airports (including Time Machines), Apple TVs and possibly OS X machines (depends on hardware, network connection method, OS release as to whether they run a sleep proxy).

The developer of that app should probably reconsider their method of license control as it likely only ever annoys legitimate users."

Hello root_wheel

Computer name change fix

OK, I think after spending months and months banging my head against the wall, spending countless hours with Apple Support and nobody being able to shed some light on this issue... I think I figured it out. It has to do with IP v6. I figured that the only way the device adds these numbers is because it is already seen on the network. So today I disabled IPv6 inside my Netgear router and guess what - no more name changing on any of my devices. At least not for most part of today. Of course, only time will tell. But if you have the problem that your devices add a (2) or a (3) to the device name, check your router. If it has an option to turn off IPv6, turn it off. Then reboot your router. Then change you device names back to normal and reboot as well. Hopefully your problem is gone. It sure worked for me and never had a name change issue ever again!

Thank you,

Martin