Iptables/fw3 marks

[Philip Prindeville]

Hi,

I want to use a mark to annotate that a packet has gone through REDIRECT.

Looking at mwan3 I see that it uses 0xfc00 for its marking.

I have a couple of questions:

(1) Why does this require 6 bits out of a 16-bit field?  Why isn't a single bit adequate?

(2) How does a package "reserve" a bit for marking such that the same bit doesn't get re-used by another package and create conflict/ambiguity?  i.e. who manages the assignment of masks and in what file is this recorded?

Thanks,

-Philip