-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 thus Giovanni Tirloni spake: | On Thu, Oct 1, 2009 at 2:02 PM, Timo Schoeler | <timo.schoeler at riscworks.net>wrote: | |> -----BEGIN PGP SIGNED MESSAGE----- |> Hash: SHA1 |> |> Hi list, |> |> I have a weird (?) problem here on a setup running CentOS 5.3 x86_64 |> (and OpenVZ, and some home-brew L2TP daemons, RIPd, BGPd, etc). |> |> There's a (VE in OpenVZ speak) virtual machine that has two ethernet |> interfaces, seen as eth0 and eth1, respectively. Those live in VLANs, |> but it's not important here. |> |> The thing is that on eth1 the default route lives, while on eth0 all |> traffic comes in. |> |> So, sending a ping to the IP address of eth0 tcpdump shows that the echo |> request (type 8) packet arrives on the machine. However, the machine |> does _not_ send an echo reply (type 0) back to the machine that pings |> eth0, maybe because it would have to emerge from eth1. |> |> One exception (an obvious one) is that IPs on the /29 where eth0 lives |> on _can_ ping eth0 and receive an answer -- this is because the packets |> don't have to take 'the default route', which lives on the other |> interface, eth1. |> |> This seems to me like decent behaviour. |> |> However, I really need eth0 to be able to be pinged from the outside |> world, it's totally okay for me that eth1 would 'answer' and send the |> echo replies instead of eth0. |> |> Is there anything I can tweak (via sysctl or whatever)? |> | | | You need a way to tell that packets originating from eth0 destined outside | should be routed to eth0. This thread should help: | | http://lists.centos.org/pipermail/centos/2009-January/070828.html | | Giovanni P. Tirloni | tirloni at gmail.com Thank you very much, Giovanni -- seems exactly to be what I need. Cheers, Timo -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) Comment: Using GnuPG with CentOS - http://enigmail.mozdev.org iD8DBQFKxajhfg746kcGBOwRAgIuAJ9FYy4k5mDBXcOp8J1RHt5b4WtcVgCghlFh 5QZ4PQchWB1By/D50zDjJHo= =UEjy -----END PGP SIGNATURE-----