I have some confusion after doing some tests on my own. I was actually doing some testing to find the optimum MTU Path for my network with DF bit set and by specifying length. I did on Cisco Router as well as on Windows PC CMD Ping command. For your information, the Cisco Router and Windows PC were tested with same LAN port and both with default MTU size at the interfaces.
By using Cisco Exteneded Ping, the maximum packet size I can insert is 1492 with DF bit set while the maximum packet size for Windiows PC with DF set is 1472.
In this scenario, can I assume that Size in Cisco Extended Ping is included IP Header but Size in Windows Ping Command is not included IP Header? Correct me if I am wrong.
my experience is 1500 Bytes in Cisco CLI correspondes to 1472 Bytes in Windows cmd.
Your 1492 might be caused by ADSL or IPSec involved?