Mac OSX VNC Screen Sharing Issue

Hi there, help needed,

Running High Sierra 10.13.2 on our Mac Mini, iMac and my Macbook Pro. The Mac Mini is used "headless" to serve music via SPDIF to the SuperNait DAC.

We were happily controlling the Mini using the in-built OSX screen sharing via WiFi. It started to get flakey, requiring toggling WiFi on/off and/or restarting the Mini to get it to show up as an option in the Finder Sidebar on the Macbook. Eventually it stopped showing up at all.

I updated all OSs, thinking a compatibility issue. No dice.

Been through Apple support and they got me to try everything I'd already tried. No luck.

1. All computers are on the same WiFi netowrk

2. All computers are logged into the same iTunes account and AppleID.

3. Users are all "Admin" level and all permissions set to allow screen sharing

I've also tried going direct to the Mini's IP address, (Using Go>>Connect to Server in Finder) but it can't find it that way either.

A router reset fixed it once for a short while but that doesn't fix it any more. Basically the Mini just refuses to show up as a computer connected to the network. Even though is definitely a computer connected to the network.

I'm at my wits end.

(We also used to be able to control iTunes on the Mini using the "Remote" App on iPhones and iPads, but the library has disappeared as an option there too.)

 

 

Winky

Original Post

I am not familiar with Apple’s inbuilt screen sharing, nor with Sierra having stopped with El Capitan on my MM, so have nothing specific to offer, but it is reminiscent of a security issue like a firewall. Has anything been updated recently (other than your deliberate updating of the IOS after the problem appeared). What about the router? Sometimes they are set for automatic firmware updating - if unsure it should be possible to search either its log or look for a date of last updating. If something had been updated, that would be an obvious place to scrutinise security settings.

I use Apple Remote Desktop across five Macs, two of which are too old for Sierra and High Sierra.  I think ARD is a free download now; used to cost $40 per client, IIRC.

Not perfectly smooth, but generally reliable.

Is that what you are already using?  I have found when I cannot connect to a client, connecting from a different host clears the blockage.

Nick

Innocent Bystander posted:

I am not familiar with Apple’s inbuilt screen sharing, nor with Sierra having stopped with El Capitan on my MM, so have nothing specific to offer, but it is reminiscent of a security issue like a firewall. Has anything been updated recently (other than your deliberate updating of the IOS after the problem appeared). What about the router? Sometimes they are set for automatic firmware updating - if unsure it should be possible to search either its log or look for a date of last updating. If something had been updated, that would be an obvious place to scrutinise security settings.

Thanks for the suggestions. No firewalls that I am aware of, but some sort of security issue with the router seems a logical possibility.

NickSeattle posted:

I use Apple Remote Desktop across five Macs, two of which are too old for Sierra and High Sierra.  I think ARD is a free download now; used to cost $40 per client, IIRC.

Not perfectly smooth, but generally reliable.

Is that what you are already using?  I have found when I cannot connect to a client, connecting from a different host clears the blockage.

Nick

I'm not using ARD, just the VNC functionality built into the OS, but will look into it.

For what it's worth, I'm running High Sierra 10.13.2 on my Macs and screen sharing works perfectly. So, to the best of my knowledge, there's nothing "broken" with OSX but maybe some kind of mac filtering or firewall etc. at the router is playing silly games.

blythe posted:

For what it's worth, I'm running High Sierra 10.13.2 on my Macs and screen sharing works perfectly. So, to the best of my knowledge, there's nothing "broken" with OSX but maybe some kind of mac filtering or firewall etc. at the router is playing silly games.

Thanks. I'll look into the router.

Macs ability to network discover has always been a disaster. You will rarely find everything discoverable in the finder side bar. Annoying but true.

However everything is still there. You need to ascertain the IP of your mini, and either fix it from the mini or assign one from the router. 

Open up screen share, it resides in your HD/System/CoreServices/Applications. Once open drag it into a location on the dock so it stays there. Now enter the IP of the mini and you should be golden moving forward.

Really, why so. These days Mac tends to use mDNS for discovery, which uses a multicast address not dissimilar to SSDP used by Windows and UPnP.

if there are discovery issues I would first look to your Wifi access point and ensure it’s correctly processing multicast addresses. If you can try disabling IGMP snooping to see if it all kicks into life...

blythe posted:

For what it's worth, I'm running High Sierra 10.13.2 on my Macs and screen sharing works perfectly. So, to the best of my knowledge, there's nothing "broken" with OSX but maybe some kind of mac filtering or firewall etc. at the router is playing silly games.

Ditto, no issues with ARD or screen sharing.

KR, J

Simon-in-Suffolk posted:

Really, why so. These days Mac tends to use mDNS for discovery, which uses a multicast address not dissimilar to SSDP used by Windows and UPnP.

if there are discovery issues I would first look to your Wifi access point and ensure it’s correctly processing multicast addresses. If you can try disabling IGMP snooping to see if it all kicks into life...

I dont know, I speak from personal experience over many years, apple is just not so good at this and even worse with network shares. Network shares being a known issue for many years, everyone has experienced the finder melting down when an mounted share is no longer available. After 10 years its still a problem.

I know its a separate issue but still annoying.

garyi posted:

Macs ability to network discover has always been a disaster. You will rarely find everything discoverable in the finder side bar. Annoying but true.

However everything is still there. You need to ascertain the IP of your mini, and either fix it from the mini or assign one from the router. 

Open up screen share, it resides in your HD/System/CoreServices/Applications. Once open drag it into a location on the dock so it stays there. Now enter the IP of the mini and you should be golden moving forward.

The issue again fixed itself with a router reset and toggled the WiFi and the mini re-appeared. I looked all around the TP router settings but found nothing much that seemed relevant.

I tried your method above, and that also got me connected OK this morning. Thanks.

However, I don't actually think it is something in the MacBook's ability to discover, though. When the Mini disappears, it also disappears from iPads and iPhones. It's probably either the Mini or the router, as has been suggested.

The Router is a TP-LInk Touch P5. What should I be looking for in the router settings? There is a thing called "SPI Firewall", but toggling that makes no difference. Simon-I-S, where would I disable IGMP? How would I check its ability to process multicast addresses?

Thanks for all the help and support thus far.

NickSeattle posted:

Winky,

Once, I had a connectivity issue like yours while using ARD.  I ended up calling Apple.  It was a short call — the tech had me toggle Sharing prefs off then on on affected machines.  Sometimes a preference gets corrupted.

A rare thing, IME.

Nick

Thanks Nick. I looked into ARD and it was over $100. I have the VNC Screen-sharing working (for now) and will stick with that if I can. (Our fall-back is to just use the TV as a monitor and a bluetooth mouse from my listening chair to control the Mini directly. It actually works just fine.)

"Toggling" things (WiFi on the Mini and the router itself) works sometimes, but less often now, for some reason. I'll try toggling the sharing preferences. Switch them off, re-start and switch them back on. Re-start again if it hasn't worked. I'm becoming more suspicious that it is the router, though.

This is unlikely to be relevant, unless it identify a pattern: the only Mac I have is my headless music Mac Mini. I control it using VNC Player’ - free standalone software, not part of Apple systems - using on both an old (Mk 1) iPad running IOS 5, and a more recent one on IOS 11.2, and a Windows10 laptop: never any problem with any. 

winkyincanada posted:
garyi posted:

Macs ability to network discover has always been a disaster. You will rarely find everything discoverable in the finder side bar. Annoying but true.

However everything is still there. You need to ascertain the IP of your mini, and either fix it from the mini or assign one from the router. 

Open up screen share, it resides in your HD/System/CoreServices/Applications. Once open drag it into a location on the dock so it stays there. Now enter the IP of the mini and you should be golden moving forward.

The issue again fixed itself with a router reset and toggled the WiFi and the mini re-appeared. I looked all around the TP router settings but found nothing much that seemed relevant.

I tried your method above, and that also got me connected OK this morning. Thanks.

However, I don't actually think it is something in the MacBook's ability to discover, though. When the Mini disappears, it also disappears from iPads and iPhones. It's probably either the Mini or the router, as has been suggested.

The Router is a TP-LInk Touch P5. What should I be looking for in the router settings? There is a thing called "SPI Firewall", but toggling that makes no difference. Simon-I-S, where would I disable IGMP? How would I check its ability to process multicast addresses?

Thanks for all the help and support thus far.

Hi Winky, this does sound like a Wifi bridge deficiency on your router, almost certainly not correctly handling IGMP that might have changed slightly with some operating system upgrades.

winkyincanada posted:
NickSeattle posted:

Winky,

Once, I had a connectivity issue like yours while using ARD.  I ended up calling Apple.  It was a short call — the tech had me toggle Sharing prefs off then on on affected machines.  Sometimes a preference gets corrupted.

A rare thing, IME.

Nick

Thanks Nick. I looked into ARD and it was over $100. I have the VNC Screen-sharing working (for now) and will stick with that if I can. (Our fall-back is to just use the TV as a monitor and a bluetooth mouse from my listening chair to control the Mini directly. It actually works just fine.)

"Toggling" things (WiFi on the Mini and the router itself) works sometimes, but less often now, for some reason. I'll try toggling the sharing preferences. Switch them off, re-start and switch them back on. Re-start again if it hasn't worked. I'm becoming more suspicious that it is the router, though.

Sorry about that.  I see it is $80 USD.  I bought it a long time ago;  with no per-seat or per-machine prcing model it has acted like a free app for me, ever after.

Free VNC is a valid alternative.

Interested in how this resolves.

Nick

essentially there is 'no problem' here beyond what pops up in the side bar of a mac finder window. Whilst it *Should* work of course, it does not always. Same for windows in network, sometimes everything appears sometimes it does not.

 

you could I suppose get worked up about it, or find the work around and move on, because computers will always be computers.

garyi posted:

essentially there is 'no problem' here beyond what pops up in the side bar of a mac finder window. Whilst it *Should* work of course, it does not always. Same for windows in network, sometimes everything appears sometimes it does not.

 

you could I suppose get worked up about it, or find the work around and move on, because computers will always be computers.

No, it's perhaps not quite that simple. I've not yet found a way to get connected when the Mini is missing from the sidebar. I've tried going straight to its IP address, but no go. (It's all working again, for now). If it fails, I'll try using the VNC-SS app directly as you suggested, rather than accessing from Finder (which seemingly can't be done if the Mini isn't showing). I have the SS app in my dock, and it works, but at the moment so does my old way. I'll let you know if it is successful next time the Mini disappears.

I think if the VNC server on the client crashes, there is nothing you can do remotely to recover.  Enterprise hardware provides remote-reboot ability.  Again, may not be relevant; but IME, sometimes somebody has to drive to the datacenter and push a button.   Someday this won’t be so.

Nick

winkyincanada posted:
garyi posted:

essentially there is 'no problem' here beyond what pops up in the side bar of a mac finder window. Whilst it *Should* work of course, it does not always. Same for windows in network, sometimes everything appears sometimes it does not.

 

you could I suppose get worked up about it, or find the work around and move on, because computers will always be computers.

No, it's perhaps not quite that simple. I've not yet found a way to get connected when the Mini is missing from the sidebar. I've tried going straight to its IP address, but no go. (It's all working again, for now). If it fails, I'll try using the VNC-SS app directly as you suggested, rather than accessing from Finder (which seemingly can't be done if the Mini isn't showing). I have the SS app in my dock, and it works, but at the moment so does my old way. I'll let you know if it is successful next time the Mini disappears.

Ah I did not realise that, that is obviously something different. I assume you have the mini to stay awake all the time?

Winky - one thing worth checking is that you've not got an IP address conflict between your Mini and something else on your network. I had this issue with a disappearing NAS which would come and go. I ran a free network checker (Fing) on my iPad which listed all the devices active on my network and found a data logger unit I was using at the time was allocated the same IP address. Changing this to a different fixed IP address made the issue go away.

James

garyi posted:
winkyincanada posted:
garyi posted:

essentially there is 'no problem' here beyond what pops up in the side bar of a mac finder window. Whilst it *Should* work of course, it does not always. Same for windows in network, sometimes everything appears sometimes it does not.

 

you could I suppose get worked up about it, or find the work around and move on, because computers will always be computers.

No, it's perhaps not quite that simple. I've not yet found a way to get connected when the Mini is missing from the sidebar. I've tried going straight to its IP address, but no go. (It's all working again, for now). If it fails, I'll try using the VNC-SS app directly as you suggested, rather than accessing from Finder (which seemingly can't be done if the Mini isn't showing). I have the SS app in my dock, and it works, but at the moment so does my old way. I'll let you know if it is successful next time the Mini disappears.

Ah I did not realise that, that is obviously something different. I assume you have the mini to stay awake all the time?

Yeah, it's set to "never sleep". (Tried wake-on-LAN and all that unreliable stuff years ago.)

james n posted:

Winky - one thing worth checking is that you've not got an IP address conflict between your Mini and something else on your network. I had this issue with a disappearing NAS which would come and go. I ran a free network checker (Fing) on my iPad which listed all the devices active on my network and found a data logger unit I was using at the time was allocated the same IP address. Changing this to a different fixed IP address made the issue go away.

James

Thanks. Good suggestion. My router lists all the devices and they all have different IP addresses (as they should). There is perhaps something hidden from this list, I guess. It's all currently working, but if it fails, I'll check the IP addresses again. Thanks.

winkyincanada posted:

Thanks. Good suggestion. My router lists all the devices and they all have different IP addresses (as they should). There is perhaps something hidden from this list, I guess. It's all currently working, but if it fails, I'll check the IP addresses again. Thanks.

Set the router & all the audio with IP addresses to DHCP & you will never have an IP address problem,  thats what the router DHCP mngr does,  its designed especially for home wifi+ethernet systems.  Leave the static IP's to very large systems & IP pro's

winkyincanada posted:
james n posted:

Winky - one thing worth checking is that you've not got an IP address conflict between your Mini and something else on your network. I had this issue with a disappearing NAS which would come and go. I ran a free network checker (Fing) on my iPad which listed all the devices active on my network and found a data logger unit I was using at the time was allocated the same IP address. Changing this to a different fixed IP address made the issue go away.

James

Thanks. Good suggestion. My router lists all the devices and they all have different IP addresses (as they should). There is perhaps something hidden from this list, I guess. It's all currently working, but if it fails, I'll check the IP addresses again. Thanks.

My router list didn't show the problem, but the using the network sniffer did so it's worth checking that out. Good luck Winky, i'll be interested to see what you find. 

James

 

james n posted:
winkyincanada posted:
james n posted:

Winky - one thing worth checking is that you've not got an IP address conflict between your Mini and something else on your network. I had this issue with a disappearing NAS which would come and go. I ran a free network checker (Fing) on my iPad which listed all the devices active on my network and found a data logger unit I was using at the time was allocated the same IP address. Changing this to a different fixed IP address made the issue go away.

James

Thanks. Good suggestion. My router lists all the devices and they all have different IP addresses (as they should). There is perhaps something hidden from this list, I guess. It's all currently working, but if it fails, I'll check the IP addresses again. Thanks.

My router list didn't show the problem, but the using the network sniffer did so it's worth checking that out. Good luck Winky, i'll be interested to see what you find. 

James

 

Thanks. I let you know how it works out.

Quick update. The Screen Sharing has been working fine for the last couple of weeks. One issue that keeps cropping up occasionally is that the Mini just disconnects itself from the network (turns WiFi off) from time to time. It is set to automatically join known networks, and only the one I want it to join is listed (so it shouldn't be getting confused). I can't think of a setting that could be wrong, and I've never experienced it with other products. Anyway, if the SS stops, it is now the first thing I check.

Just to be clear, it isn't/wasn't the whole issue, though. Previously, the SS was flakey even with the WiFi definitely on the right network, and the Mini demonstrably connected to the network and internet. But it likely made trouble-shooting more difficult, until I noticed it as an occasional issue.

 

Thanks again to everyone for their help.

Simon-in-Suffolk posted:

Really, why so. These days Mac tends to use mDNS for discovery, which uses a multicast address not dissimilar to SSDP used by Windows and UPnP.

if there are discovery issues I would first look to your Wifi access point and ensure it’s correctly processing multicast addresses. If you can try disabling IGMP snooping to see if it all kicks into life...

Hi Simon (it's Simon!).

could you elaborate what the IGMP is doing or meant to do. I'm not familiar. This is very interesting and may help me diagnose..

I have an apple network and Macs.  IGMP snooping is already disabled.  Over the last 4-5 months, my time machine backups have been acting up ( can't find backup share, timeout ). When I tried browsing the (any) shares I found I couldn't connect from Finder.   I found that a force quit of Finder made them 'findable' again.  Nothing else was needed. Printer has been bulletproof so I think Bonjour/mDNS is working ok?  Seems local to the Finder/TM code?

I had similar irritating problems with my MacMini.

If you Google "mac mini wifi problem" you will discover that this is a known issue. The only solution I found was to give up using wifi on the Mac Mini and connect it through Ethernet, then I bought a Melco wich is (for music) much better than the Mac Mini in all aspects.

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