On Tue, 2015-07-07 at 17:27 +0200, Matteo Croce wrote: > 2015-07-07 10:07 GMT+02:00 Hannes Frederic Sowa < > han...@stressinduktion.org>: > > > > > > On Mon, Jul 6, 2015, at 21:44, Matteo Croce wrote: > > > 2015-07-06 12:49 GMT+02:00 <valdis.kletni...@vt.edu>: > > > > On Thu, 02 Jul 2015 10:56:01 +0200, Matteo Croce said: > > > > > Add option to disable any reply not related to a listening > > > > > socket, > > > > > like RST/ACK for TCP and ICMP Port-Unreachable for UDP. > > > > > Also disables ICMP replies to echo request and timestamp. > > > > > The stealth mode can be enabled selectively for a single > > > > > interface. > > > > > > > > A few notes..... > > > > > > > > 1) Do you have an actual use case where an iptables '-j DROP' > > > > isn't usable? > > > > > > If you mean using a default DROP policy and allowing only the > > > traffic > > > do you want, > > > then the use case is where the port can change at runtime and you > > > may not > > > want > > > to update the firewall every time > > > > Can't you use socket match in netfilter to accomplish exactly that? > > You mean the owner --uid match? > Yes sort of, but my was a different goal, I want just to disable any > kind of reply from a specific interface (usually WAN) unless there is > a listening socket, to mitigate port scanning and flood attacks > without having a firewall.
I was more thinking about the xt_socket match: -m socket in the INPUT chain. > Obviously you can do it with a firewall, > but why do we have /proc/sys/net/ipv4/icmp_echo_ignore_all when we can > drop ICMP echoes? Same arguments apply to that knob, but it is already imported and cannot be changed anymore. Nowadays we try to avoid adding new sysctls. Bye, Hannes -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
