Let me explain some more. If you want all interfaces, Linux provides a way to use a single socket, and still manage the source addresses: IP_PKTINFO. Then interface addition/deletion does not involve userspace. This is currently not used by most software (bind9, ntpd, heimdal-kdc) however, so they use the older approach used on other unix, to bind one socket per interface. The problem is, when binding to a specific interface, you have to track interface addition/deletion. Some approaches are better than others, but restarting the process or waiting for it to poll an interface, are not ideal. For the above case, using a single socket with IP_PKTINFO, eliminates the need to track interface add/remove/address change, correct? Now the other use case, listening only on certain interfaces, maybe the features don't overlap (automatic interface add/remove vs selective interface listen), and the best that can be done using the socket API is for userspace to drop the packet, or use iptables to send the ICMP Port Unreachable... both less than ideal. Is there a 3rd option? Jeremy If you want to bind to only certain interfaces, On Tue, 2007-11-20 at 14:07 +0800, Herbert Xu wrote: > Jeremy Jackson <jerj@xxxxxxxxxxxx> wrote: > > > > Is there a solution that lets a single socket "not-bind" to certain > > interfaces? > > By binding it to a specific interface? > > Cheers, -- Jeremy Jackson Coplanar Networks (519)489-4903 - To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
