I run PPPoE Servers on my network where clients connect. The network is routed and all traffic eventually ends up going through a L2TP VPN. The VPN part of the network is usually a few hops away from the actual PPPoE servers.

PPPoE is set at 1492. L2TP is 1460. Change TCP MSS is enabled on the L2TP only (not enabled on PPPoE servers) Do I need to lower the MTU at the PPPoE servers because of the VPN upstream? This setup has been running great for months. Occasionally there are a few things that don't seem to act just right. I was suspecting MTU settings.

Just wondering if it matters that there is a VPN somewhere further up. Any advice would be great.