On Wednesday 09 June 2004 15:18, Julian Anastasov wrote: > Hello, > > On Wed, 9 Jun 2004, Denis Vlasenko wrote: > > I observe that UDP sockets listening on ANY > > send response packets with ip addr derived from > > ip address of interface which is used to send 'em > > instead of using dst ip address of client's packet. > > > > I was bitten by this with DNS and NTP. > > The problem is in the apps. You have some options: > > - use sockets listening on ANY and using sendmsg with IP_PKTINFO > and providing the desired src IP in ipi_spec_dst > > - you can also create many listener sockets listening on > particular src IP and to reply using the socket where the > request is received, because the kernel does not know any > association between request and reply packets if the listener > is bound to ANY. Aha! That's why ntpd is so eager to bind to everything imaginable! (Which does not help BTW with non-permanent interfaces like ppp, tun etc). /me googling for that IP_PKTINFO thing... -- vda - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
