Re: [iptables PATCH] doc: libxt_MARK: OUTPUT chain is fine, too

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Wed, May 20, 2020 at 01:08:22AM +0200, Phil Sutter wrote:
> In order to route packets originating from the host itself based on
> fwmark, mangle table's OUTPUT chain must be used. Mention this chain as
> alternative to PREROUTING.
> 
> Fixes: c9be7f153f7bf ("doc: libxt_MARK: no longer restricted to mangle table")
> Signed-off-by: Phil Sutter <phil@nwl.cc>
> ---
>  extensions/libxt_MARK.man | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/extensions/libxt_MARK.man b/extensions/libxt_MARK.man
> index 712fb76f7340c..b2408597e98f1 100644
> --- a/extensions/libxt_MARK.man
> +++ b/extensions/libxt_MARK.man
> @@ -1,7 +1,7 @@
>  This target is used to set the Netfilter mark value associated with the packet.
>  It can, for example, be used in conjunction with routing based on fwmark (needs
> -iproute2). If you plan on doing so, note that the mark needs to be set in the
> -PREROUTING chain of the mangle table to affect routing.
> +iproute2). If you plan on doing so, note that the mark needs to be set in
> +either the PREROUTING or the OUTPUT chain of the mangle table to affect routing.

You have two choices:

* Set the mark in filter OUTPUT chain => it does not affect routing.
* Set the mark in the mangle OUTPUT chain => it _does_ affect routing.

Are we on the same page?