K-sPecial wrote:
> I'm trying to figure out if the IP max option length of 40 includes
> buffer space supplied by the length field of the source routing ip
> option, per say, or if that buffer can be extended. My guess is
> otherwise, since IHL maxes at 60 bytes. Although, my mind reminds me
> that the stack could still find the ip header boundary even if it was
> 120 bytes by examining the lengths in these option fields. Any input
> is gratefuly accepted.


The header length includes everything in the header, included the
contents of all of the options. An option cannot extend past the area
defined by the header length. The 60 byte header limit severely limits
the usefulness of some options. IP6 completely changes the way options
are handled (it's a chain of extension headers instead of a list of
options), and it largely eliminates the size restrictions.