From: John Beckett 

"Geo"  wrote in message
news::
> Are you sure it's 64K "Bytes" and not "Bits"?

Yes, I'm certain. You can try this (-l is -L for length):

ping -l 51000 cisco.com
ping -f -l 51000 cisco.com

Actually, I just tried this and it didn't work. Maybe cisco are rejecting
pings that are excessively long. Try it on a local computer. You can use
any number up to almost 64K for the length.

The -f means "don't fragment". The result will be that the ping
will fail immediately because you are (probably) on an Ethernet where the
maximum frame size is 1500 bytes.

In bytes:   1500 = 20 (IP header) + 8 (ICMP header) + 1472 (max ping data)
Therefore this is the max for Ethernet: ping -f -l 1472 cisco.com

John

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