Every incoming packet goes through "input routing". The result of that routing is either to receive the packet locally, drop, or forward it.
There is a hidden "local" routing table, that is used to do routing for incoming packets. It is populated automatically (e.g when u add an new local interface) You can display this table and it will help you understand the behaviour of your system: ip route list table local On 04/08/2009, Lev Olshvang <l...@vboxcomm.com> wrote: > > Shahar , > Thanks .... > > see below : > Shachar Shemesh wrote: > I'll just point out that my Multicast understanding is a bit tenuous. > > Lev Olshvang wrote: > Evening all, > > > But if I change the interface IP address to other network, these packets > are ignored at IP layer (data link layer got it since RX count is running > according to ifconfig ) > I have tcp ip forwarding set to 1 and application sets multicast socket > option to join the multicast group. > > Did you change the IP address after the socket is up? Multicast needs to > perform some handshaking before it can start sending data, and this > handshake might be done only at the "start". > > > Since this is my network driver , I reload it and set IP after reload, > as well I put some printk in it so I see data link accepts packages in > either case. tcpdump also shows these packets. > > Also, I would start the debugging by running a sniffer and seeing whether > the packets actually leave the machine, and if so, with what destination MAC > address. > > I have no problem with MAC ( driver gets the packets), I put also some > printk in net/ipv4/route.c and I see this packets are discarded at IP layer. > > Shachar > -- > Shachar Shemesh > Lingnu Open Source Consulting Ltd. > http://www.lingnu.com > > > > _______________________________________________ > Linux-il mailing list > Linux-il@cs.huji.ac.il > http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il > > _______________________________________________ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
