Proper MTU Size + Uverse

[mark1210]

Hello,

I'm in the process of installing PF Sense behind my Pace 5268 U-verse router.

The PFSense Box will be in the DMZ+ mode (so that it gets the public IP address).  Everything else will be behind the PFSense on the LAN side.

On my MAC connected directly to the 5268, I believe the MTU setting is 1492 based on my ping testing with various sizes.

In PFSense, do I plug the 1492 MTU in both the LAN and WAN interfaces?
Does the MTU setting change (decrease) if I connect to the PFSense box (which is behind the RG)?

Thanks