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Computer name changing constantly (two or one network interfaces enabled)


Stefan Milev
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Hello folks. 

 

I have this thing going on here on my rig with Yosemite DP8.

 

Normally I have two network interfaces active LAN and WiFi on the same network. I have also file sharing active. 

My computer name was set to Stefan's iMac initially. Lately though I see that it changes to Stefan's iMac (1), Stefan's iMac (2), Stefan's iMac (3) and so on up until 10 is the highest I've seen so far. An example here:

 

Screen_Shot_2014_09_26_at_12_35_14.png

 

So one would say: "Sure, you can expect that. You are using two network interfaces at the same time on one network with the same netbios names!"

So the simple test would be to disable one interface and see what will happen, right? And so I went on and disabled LAN as WiFi n is better than 100Mb network cable connection.

Unfortunately I still experience the same behaviour as before. In Finder I see this:

 

Screen_Shot_2014_09_26_at_12_49_09.png

 

You can see here many versions of it but the hack is the same with only one interface active.

If I try to change it back to Stefan's iMac from Stefan's iMac (whatever number), in couple of second or if I close System Preferences it goes back or changes to some other number. 

 

How do I prevent this from happening? I searched and I can see that people with real Macs have or had this also, but I didn't find a working solution. 

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Hello folks. 

 

I have this thing going on here on my rig with Yosemite DP8.

 

Normally I have two network interfaces active LAN and WiFi on the same network. I have also file sharing active. 

My computer name was set to Stefan's iMac initially. Lately though I see that it changes to Stefan's iMac (1), Stefan's iMac (2), Stefan's iMac (3) and so on up until 10 is the highest I've seen so far. An example here:

 

Screen_Shot_2014_09_26_at_12_35_14.png

 

So one would say: "Sure, you can expect that. You are using two network interfaces at the same time on one network with the same netbios names!"

So the simple test would be to disable one interface and see what will happen, right? And so I went on and disabled LAN as WiFi n is better than 100Mb network cable connection.

Unfortunately I still experience the same behaviour as before. In Finder I see this:

 

Screen_Shot_2014_09_26_at_12_49_09.png

 

You can see here many versions of it but the hack is the same with only one interface active.

If I try to change it back to Stefan's iMac from Stefan's iMac (whatever number), in couple of second or if I close System Preferences it goes back or changes to some other number. 

 

How do I prevent this from happening? I searched and I can see that people with real Macs have or had this also, but I didn't find a working solution. 

Only thing I can think of is flushing you DNS cache...

 

But this is also a developer preview so don't expect everything to work flawlessly. 

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I'm having the same problem whether I use ethernet, wifi, or both.  I'm still exploring the possibilities but one thing I've noticed on my system is that just before the name "changes" I lose connectivity to my NAS (can't ping it, browse it, mount it, etc.) while its still up for other machines on my network.  Other devices are still visible.

 

Right now, I'm not sure if this is related, just a symptom, or something else.  By any chance, do you have a Synology NAS on your network?

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Sorry--I missed the obvious in the screen shot and could have saved a post and response!

 

OK, so are you using the Synology just as a NAS or is it also DHCP, DNS, Plex, and/or other services that you had to specifically enable?

 

For me, the following steps can often (but not always) reproduce the problem.

 

  • Start pinging the Synology (for me, ping 192.168.1.21)
  • Go and rename my Mac back to its normal name in the sharing preferences (remove the (5) )
  • In a few moments, my ping will start failing
  • I can still ping other devices on my network and the Internet
  • Eventually, the name changes and a (x) is added
  • Pinging resumes and another Mac shows up in sharing

 

For what its worth, I'm running DP8 and I've had this problem with the latest Synology release of 5.0 as well as their 5.1 beta.  I'm pretty sure I also had the same problem with DP7.

 

To anyone else reading this who doesn't have a Synology, I apologize.  I'm not trying to hijack the thread but trying to explore similarities in Stefan's and my problems.

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So I believe I found the issue, but the news are not so good. 

Synology in my case has nothing to do with the issue (I use it as a NAS and iTunes music share).

I think Time Capsule is the issue. It has Bonjour sleep proxy service which basically "highjacks" the IP of the hack when it goes to sleep and replies to multicast DNS queries. 

28/09/14 09:21:11,000 kernel[0]: en0 duplicate IP address 192.168.110.112 sent from address d8:30:62:xx:xx:xx

(d8:30:62:xx:xx:xx is the mac address of my Time Capsule.)

 

 

 

 

This helps the computer to save power and if it's needed to wake it up, Time Capsule sends wake packet and wakes the computer.

 

The problem is that when the hack wakes up the host name is already registered with another mac address on the same IP in my firewall (pfsense) DHCP tables.

This is seen as there is another machine with the same name

28/09/14 09:42:26,491 discoveryd[48]: Basic DNSResolver  Re-Binding to random udp port 61139

This is log entry from pfsense firewall when the hack wakes:

kernel: arp: 192.168.110.112 moved from d8:30:62:xx:xx:xx to 94:de:80:xx:xx:xx on vr0

and the OS decides to change the name:

28/09/14 09:43:45,250 configd[25]: setting hostname to "Stefans-iMac-6.local"
28/09/14 09:43:45,336 discoveryd[48]: Basic Bonjour Changing computer name from Stefan’s iMac (7) to Stefan’s iMac (4)

 

 

 

 

All that is still fresh in my head and maybe it doesn't make any sense to all, but I'm giving the raw data which is not structured yet. I'm still investigating this.

I can also say that this is an issue for a very long time and has nothing to do with Yosemite being beta and such.

 

These are my findings, feel free to correct me if you think I'm wrong.

 

 

Maybe disabling sleep proxy client will solve the issue. Look here how to do it.

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So I believe I found the issue, but the news are not so good. 

Synology in my case has nothing to do with the issue (I use it as a NAS and iTunes music share).

I think Time Capsule is the issue. It has Bonjour sleep proxy service which basically "highjacks" the IP of the hack when it goes to sleep.

 

Interesting find.  In my case, I don't have a Time Capsule, but do have two Apple TVs (a 2 and 3) which are supposed to act as the proxy client if no Time Capsule is present.  Additionally, the Synology is my DHCP/DNS server which may explain why I'm having Synology-related issues.  Will explore further and see if I can find log entries similar to yours.

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So, interestingly enough, I moved my DNS and DHCP off of the Synology and onto my router (T-Link).  No change.  I then rebooted my Synology and unplugged the power to my Apple TV 2 (I have the Apple TV 3 still on).  Ever since doing that, my Mac has NOT renamed itself.  It has kept its "normal" name now for two days and still sleeps/wakes up just fine.

 

Mind you, I could never get the wake on LAN to work with or without Apple TV.  If my Mac is asleep, it won't wake up for "Back to My Mac" nor for Apple TV trying to connect to Home Sharing. Yes, Wake on Ethernet is enabled in the BIOS.  So, for now, I'm good (without name changes) without changing anything on my Mac config.  Unfortunately, I did the Synology reboot and Apple TV 2 unplugging at the same time so I can't verify for sure which fix worked.  However, since you're having the same problem, never used the Synology as a DHCP/DNS server, and I agree that without those two, there's no part Synology should be playing on network configurations, I'm inclined to believe that for me, it was a problem of having two Apple TVs on my network and (maybe) both were trying to act as a proxy.

 

Still needs more investigation on my end and I should be able to plug in the second Apple TV and deduce whether or not the problem comes back.

 

Just curious:  with the Yosemite GM candidate coming out today, are you still experiencing the same issues?

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If you can't wake the Mac on demand that means to me that there is no sleep proxy server working despite the connected ATV3. This according to my theory means no name changing. Can you check the router's log to see if your computer's IP is being assigned to different MAC addresses? This should confirm that there's no sleep proxy server in your network.

 

On GM candidate I still have the issue yes.

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Hi Stefan,

 

I have exactly the same issue in a similar setting:

 

- TimeCapsule, Synology-NAS, a Macbook-Pro and a Desktop-Hackintosh

- using OSX-Yosemite-Beta on the Macbook-Pro for some weeks now and 10.9. on the Hackintosh > without the Synology-NAS I never had the problem with the changing and multiple computername > so I don't think OSX 10.10. is the problem

- Two weeks ago I bought a Synology-NAS. Since then I have the same problem with automatic changes of the ComputerName with multiple numbered entries in the sidebar on both computers

-  I've tried nearly any setting at the Synology-DSM (switched on/off the smb and bonjour-services, fixed IP-Adress etc..) with no effect

-  also changes ComputerName, HostName and LocalHostName with scutil > no lasting effect

 

- but maybe I've found a solution (works now for a day): In the timecapsule-settings I had assigned fixed IPs to my devices. So I deleted the entries for the macbook an the hackintosh > no more changing of the computername

 

I'm only a semi-advanced user, so I don't have a clue why this worked, but I highly assume it's a problem between the NAS and the TimeCapsule.

 

Johan

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So yes, you're right Stefan.  When the Mac is sleeping, there's no other device (i.e., my only ATV that's powered on at the moment) acting as a proxy.  Thus, there are probably multiple issues going on for me.  The duplicate names was definitely a problem and an indicator of a proxy not relinquishing the name on the network and now the fact that there are no proxies.  For me, right now, I'm not getting the duplicate names anymore and the Mac has settled into its real name without any (5) after it.  I do want it to sleep but running into the other room to wake it in order to watch Apple TV is quite annoying.

 

To Johan:  it does seem weird that we're all running into this issue with Synology on our network while I haven't seen anyone chime in with the same problem without one.  But, like Stefan said earlier, I'm not sure how the Synology would/should be involved.

 

I plan on testing further this weekend with a lot of configuration changes, reboots, sleeps, wakes, and repeats.

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About the static IP's I didn't have them set in time capsule. My pfsense firewall is in charge of all DHCP and routing in general in my network. Time Capsule is set to bridge mode. I will also continue looking at this issue and pay attention to Synology. 

 

Edit:

Do you guys have iTunes server enabled on the Synology?

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I am having this issue as well, but I do not have a Synology.

What I do have:

4th gen Airport Extreme
Airport Extreme 802.11ac
Airport Express 1 Gen
Two Apple TVs 2 gen

 

The problem started when I set up the iMac to Sleep at Midnight and wake up at 6 AM.

I have tried to make DHCP reservations, but this did not solve the problem. The only thing that did was to stop the duplicated computer names was to prevent my iMac from going into sleep.

I am running Yosemite Beta 4 on my Macbook, which is rarely on, and my iMac. The problem is only apparent on the iMac.

Hope this helps.

Mark

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Thanks for your input. I also agree that this is connected to sleep. My hack sleeps all the time when it's not used. I never turn it off. That's one of the reasons this is happening. 

In the logs I clearly see that name is changing on wake up.

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In addition to my first post: Deleting the DHCP-Reservations in timecapsule didn't solve the problem permanently.

And I have seen it also after waking up from sleep.

But I don't know why it's happening only for the past 3 to 4 weeks. Never had the problem in the past with the same devices. And Mark has no Synology. So maybe a Yosemite-Issue after all (the only thing we have in common)?

 

Johan

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Hey there-- I joined this forum as I was having the same issue. I've got a Mac Pro, Synology (though I think it's unconnected), two Apple TVs 3rd gen, and an AirPort Extreme 6th gen.

 

I was plagued by this issue until I logged into Back to My Mac on the Airport Extreme. Since then, it's been working without incident. I wonder if this makes it so the APE manages the Wake on LAN function. Maybe the Apple TVs doing this for Yosemite macs is not working properly?

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Hey there-- I joined this forum as I was having the same issue. I've got a Mac Pro, Synology (though I think it's unconnected), two Apple TVs 3rd gen, and an AirPort Extreme 6th gen.

 

I was plagued by this issue until I logged into Back to My Mac on the Airport Extreme. Since then, it's been working without incident. I wonder if this makes it so the APE manages the Wake on LAN function. Maybe the Apple TVs doing this for Yosemite macs is not working properly?

 

This is highly likely.  I haven't had a single issue with it renaming since I turned off one of the two Apple TVs.  The one that I shut off was an ATV 2 while the one remaining on is an ATV 3.  Additionally, I can >sometimes< wake the "Mac" from sleep by browsing a shared library from my iPhone (such as iTunes music).  However, this is inconsistent and sometimes the Music app on the phone won't even show that there's a shared library available even though iTunes was running on the Mac when it went to sleep.

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I installed Yosemite in MacBook Pro late 2010 and am observing the same issue. Name started to change. Never had this in Mavericks so for me totally Yosemite bug, but on the net I've red that people have it on other versions of the operating system. 

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