-f switch sets the Do Not Fragment bit on the ping packet. By default, the ping packet allows fragmentation.
In the ping command, the –l option means to send the buffer size in bytes. It is followed by the number of bytes for buffer size.
You can combine -f and -l to guess the maximum frame size by trial and error.
“Packet needs to be fragmented but DF set”
The frame is too large to be on the network and needs to be fragmented.
ping www.moviescope.com –f –l 1500