ip_forward and conf/*/forwarding

I have two net interfaces on my computer: eth0 and ppp0.
So I can control forwarding between interfaces through special
files on proc file system:

/proc/sys/net/ipv4/ip_forward
/proc/sys/net/ipv4/conf/all/forwarding
/proc/sys/net/ipv4/conf/default/forwarding
/proc/sys/net/ipv4/conf/eth0/forwarding
/proc/sys/net/ipv4/conf/ppp0/forwarding

How IP packet forwarding is changed when I put 0/1 to particular
interfaces? If I put 0 to conf/eth0/forwarding file, then forwarding
*from* eth0 is disabled or forwarding *to* eth0 is disabled, or in both
directions ? If I put 1 to conf/default/forwarding, then forwarding
through eth0 will be enabled despite conf/eth0/forwarding contains 0,
or maybe conversely: if I put 0 to conf/default/forwarding then
forwarding through eth0 will be disabled despite conf/eth0/forwarding
contains 1? Similar question about connection of conf/all/forwarding
and ip_forward values with conf/eth0/forwarding and influence of them
altogether on packet forwarding on eth0.


--
Rafal

On Jul 15, 6:38 pm, Rafal Dabrowa <rdsbr...@poczts.onet.pl> wrote:
> I have two net interfaces on my computer: eth0 and ppp0.
> So I can control forwarding between interfaces through special
> files on proc file system:
>
> /proc/sys/net/ipv4/ip_forward
> /proc/sys/net/ipv4/conf/all/forwarding
> /proc/sys/net/ipv4/conf/default/forwarding
> /proc/sys/net/ipv4/conf/eth0/forwarding
> /proc/sys/net/ipv4/conf/ppp0/forwarding
>
> How IP packet forwarding is changed when I put 0/1 to particular
> interfaces? If I put 0 to conf/eth0/forwarding file, then forwarding
> *from* eth0 is disabled or forwarding *to* eth0 is disabled, or in both
> directions ? If I put 1 to conf/default/forwarding, then forwarding
> through eth0 will be enabled despite conf/eth0/forwarding contains 0,
> or maybe conversely: if I put 0 to conf/default/forwarding then
> forwarding through eth0 will be disabled despite conf/eth0/forwarding
> contains 1? Similar question about connection of conf/all/forwarding
> and ip_forward values with conf/eth0/forwarding and influence of them
> altogether on packet forwarding on eth0.
>
> --
> Rafal

your question was How ----
you should read more tutorials here is some info taken from a book
Understanding Linux Network Internals By Christian Benvenuti .

http://books.google.com/books?id=yy7...dzpS9DbldqFvG0



good luck

zaher el siddik
http://elsiddik.blogspot.com/

elsiddik wrote:
> your question was How ----
> you should read more tutorials here is some info taken from a book
> Understanding Linux Network Internals By Christian Benvenuti .
>
> http://books.google.com/books?id=yy7...dzpS9DbldqFvG0

Thanks.

--
Rafal