local destination interface matching

Henrik Nordstrom hno@marasystems.com
Thu, 25 Oct 2001 18:40:02 +0200

Nigel Kukard wrote:

> 1. firstly by listing iptables rules with iptables -vnL i see that the default
>    interface is set to  *  , what would be the correct way to set this in a
>    script? (apart from leaving it out), i've seen you can use "any" or "+", not
>    sure which is most sane. anyone?

From the iptables manual page:

              match.   If  this option is omitted, the string "+"
              is assumed, which will  match  with  any  interface

but experimenting have shown that this is not actually the case, even if
functionally equivalent.

However, "any" or "*" is not a valid interface name to use for the
option. If you use "any" then iptables will literally match the
interface "any", and "*" is not even accepted as a interface name.

"" appears to be read identically to not specifying any interface

> 2. is there a way i can match a packet that is going to hit a local port other
>    than using an IP? i see in the LOG's its interface is just blank, is there
>    a way to match this?

The INPUT chain.

> 3. would anyone recommend against using the tcp-window-tracking code? i've read
>    the mailing list a few months back & didn't really find any yes/no answers.

Not very widely tested I think, and MAY break some things. But test it
anyway in a lab environment, and if you find it suitable use it.

Henrik Nordström
MARA Systems AB, Sweden