I have been having this issue off and on for about 2 weeks (possibly more) where I loose internet connection on some devices while others work just fine.   Here are the symptoms. 

1) Happens both with wired and wireless connections. 
2) I have between 25 and 35 Clients connected when this happens. 
3)  CPU on the router shows no signs of stress. 
4)  When I reboot the router or cable modem,  the devices are able to access the internet. 

5) When this issue is occurring,  I can Browse to the router without issue.  

6) If I wait long enough,  usually the problem will disappear from the device.  
7) It is not always the same devices, though on my work computers I have not experienced the issue.    

8) I do have all the antivirus running on the router. 

9)  WHen this is happening speed test on router works fine

10)  I try to connect using the IP address and it also does not work making a DNS issue less likely

11)  Spectrum is my provider.   I don't get any Errors when this occurs on the browsers..  Just never get the page to load.   Looking at the browser network diagnostic page it appears that some things may get through but most times out after 30 seconds.  If anything goes get through it is 20+ to first byte.

12)  I have a netgear genie CM600.  It is showing 24 Locked downstream and 4 Locked up stream.   4 upstream are not locked and I am not sure why.  Not a lot of Events in Log as I cleared it a few days ago.    I have two Missing BP Configuration settings that I think popped up when I reboot the cable modem.  I believe this is normal. 

As I said,  When this happens the computer or phone cannot connect to the internet though it clearly can get to the router.  Where I am having a hard time is how it comes and goes and does not effect certain devices.  It feels like hitting a max device wall somewhere but don't see any evidence.  Does not feel hardware related to me.  Either router/modem or upstream..  



I have seen other posts describing what appears to be a similar issue.  Any thoughts?  Is there a beta version of firmware I can try?  I really dont' want to engage spectrum yet as it is painful and I don't know what they would be able to do given it does not affect all devices in the house. 

Any suggestions would be most helpful.