IP routing should be turned off by default. You will also need to edit your /etc/sysctl.conf file so that the line that reads: net.ipv4.ip_forward=0 reads net.ipv4.ip_forward=1 This will enable IP forwarding on all interfaces; if you want to enable it on just one interface then you will need to remove the previously stated line and add a line in /etc/sysctl.conf that reads: net.ipv4.conf.<interface>.forwarding=1 ## Replacing interface with the appropriate interface (ex. eth0). I also want to remind you that enabling ip routing on any interface is a security risk, so be warned. Also look out for the response from my friend Eric Davis, he is explicitly looking into this just for you; so if you still have issues maybe he can provide some insight. On 6/18/06, Fabian Arrotin <fabian.arrotin at arrfab.net> wrote: > > Hummh, maybe the following question may seem silly, but have you enabled > ip routing on your CentOS box ? > What's the result of cat /proc/sys/net/ipv4/ip_forward ? > If you have enabled ip routing , maybe have a look at your firewall > rules to be sure that you don't drop any packets ... > > On Sun, 2006-06-18 at 15:06 -0400, Michael B Allen wrote: > > I have two interfaces on a centos machine with IPs 192.168.2.15 and > > 192.168.3.15. The routing table is: > > > > # route > > Kernel IP routing table > > Destination Gateway Genmask Flags Metric Ref Use > Iface > > 192.168.3.0 * 255.255.255.0 U 0 0 0 > eth1 > > 192.168.2.0 * 255.255.255.0 U 0 0 0 > eth0 > > 169.254.0.0 * 255.255.0.0 U 0 0 0 > eth1 > > default 192.168.2.1 0.0.0.0 UG 0 0 0 > eth0 > > > > The gateway 192.168.2.1 is a wireless router on which I have a static > > route for 192.168.3.0/24 to 192.168.2.15. > > > > The problem is I cannot communicate between these networks. If I ping > > from a machine on 192.168.2.0 to a machine on 192.168.3.0 it never makes > > it. If I run tcpdump -i eth0 on the machine with two nics, I can see the > > ICMP packets coming in so I know the static route on the wireless router > > is working. If I run tcpdump -i eth1 I cannot see the ICMP packets. So > the > > routing is wrong. I can successfully ping the machine on the 192.168.3.0 > > network from the machine with two interfaces. > > > > I would think that a packet sent from 192.168.2.100 for 192.168.3.128 > > would go to the gateway, get sent to 192.168.2.15 which it would go > > though the above listed routing table, match 192.168.3.0 and get sent > > to eth1. What am I doing wrong? > > > > Mike > > > > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.3 (GNU/Linux) > > iD8DBQBElaynnVkHo1a+xU4RAsomAJ9rk3Sv0llEQA3nOH4W0E8Z4JuxBACcD2Wb > M4CTUmS5yAmfik1STh7PZu4= > =NdNn > -----END PGP SIGNATURE----- > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > > > -- Thx Joshua Gimer -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20060618/e734610c/attachment-0005.html>