Since setting up a new PPPoE server (the old one died) we now have a problem we didn't have before. Customers will suddenly find that they can not go to Netflix (even the website netflix.com will not load), Yahoo Mail (yahoo.com loads slowly but mail.yahoo.com will not load at all), fast.com loads but the speed test will never start. They can go to hulu.com or amazon.com but no show/movie will ever load, it just sets there like's it buffering.. At the same time they can go to ebay.com, google.com, gmail, msn, youtube (and play youtube videos just fine).
Reboot the radio and they can go everywhere again.
Something notable is the fact that before the old PPPoE server crashed, in the 10+ years we have been doing PPPoE we never had MSS Clamping turned on on the radios (starting with the old Canopy, then ubiquiti and now a mix of FTTH, canopy, 450i and ePMP). It's off by default and everything always worked so I never messed with turning it on.
Immediately after we got the new PPPoE server up and running 1/2 the internet didn't work for anyone. People could go to MSN, youtube, ebay, google, all that but just as above, no netflix, no yahoo.mail , fast.com would load but not run . Turning on MSS Clamping fixed it, mostly because now it still happens randomly even though everyone has MSS Clamping turned on now. If you turn MSS Clamping off you lose 1/2 the internet. So I'm pretty sure this is an MTU/MRU , PPPoE problem of some kind but I've packet captured and wiresharked myself silly and figure out what the problem is.