LARTC - Jul 2005 - About multihop route decision without Julian''s patches

As I''ve read in
http://gnumonks.org/papers/netfilter-lk2000/presentation.html, there''s
said about the "nat" netfilter table:
"This table is different from the ''filter'' table, in that
only the
first packet of a new connection will traverse the table. The result
of this traversal is then applied to all future packets of the same
connection."

I imagine that the result of this traversal is stored in a kernel
table, dumpable through "/proc/net/ip_conntrack". There is no
information about the destination device of the route... When is the
route decision made? After setting all the information gathered from
ip_conntrack, or _before_ that? It isn''t clear to me, if the
"applying
of the result of the traversal" is applied in the PREROUTING or the
POSTROUTING nat chain.

I think I better look at the source code... but it''s quite hard for me
to understand the data structures there. If not an answer about my
question, I''d agree for a link to the documentation of all net-code
data structures of the linux kernel.

Thanks :)