Finding Max MTU size

[randomName]

So I searched a little on finding my Max MTU size. Did my tests and I'm a little confused

ping www.google.com -f -l 1500
Packet needs to be fragmented but DF set.

I get to 1470. I go up to 1472 and that's the highest MTU I have before it gets fragmented.

Instructions say to add 28 to my Max MTU size but that brings me back to 1500 which should be the Max MTU, but when I ran the test at 1500 it said 'Packet needs to be fragmented but DF set.' That's where I'm confused. Is my Max MTU 1472 or 1500 ?

I'm on Cable, and the router MTU was left at 1500. I'm also on Merlin 384.10_2, and using FreshJR, and the test was done PC>Router>Cable modem, not PC>Cable modem

 

[ColinTaylor]

The ping packet size doesn't include the IP/ICMP headers which is 28 bytes.

So your MTU is the ping packets size (1472) + the headers (28) = 1500.

 

[randomName]

The ping packet size doesn't include the IP/ICMP headers which is 28 bytes.

So your MTU is the ping packets size (1472) + the headers (28) = 1500.

So does anything need to be set up or is everything fine?

 

[ColinTaylor]

So does anything need to be set up or is everything fine?

Everything's fine.