Mac OSX VNC Screen Sharing Issue

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.

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

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?

Yes.  Preventing sleep improves reliability.  Theoretically, remote waking is possible, but it is an art I gave up pursuing.

Nick

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

NickSeattle posted:

IME, sometimes somebody has to drive to the datacenter and push a button.   Someday this won’t be so.

Someday... you mean when everything has integrated server management and IP addressable power switches?

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.