Re: correlation between the WAN MTU and security for the LAN.
So to answer you I am on Verizon Fios. I thought Fios was 1500 MTU but I guess not for watching streaming media for the long duration. I know that when I set my MTU to default (1500 greyed out) in the Shibby enabled RT-n12 b1 router I get my live TV streaming interrupted routinely. When I set to manual and something lower than 1500 well I only tried 1425 1420 the streams just keep playing on my 3 devices.