Chaging MTU Settings

[scr1b3]

I found I don't receive this error "Packet needs to be fragmented but DF Set" when I do a " ping -f -l 1400 www.yahoo.com ". Then I set MTU to the the value of 1400 and reboot the machine. After reboot, I did a another " ping -f -l 1400 www.yahoo.com " and got "Packet needs to be fragmented but DF Set" error again. I lower the value again and another reboot, I get the same error.

I think I'm doing some thing wrong here - Please help.

 

[DelJo63]

As I recall, there's an 8 byte header, so if MTU is 1408, then ping -l 1400 should be clean.