I did some more tests If you set net.ipv4.conf.default.forwarding=1 and reboot, this is what is observed
grep -v xx /proc/sys/net/ipv4/conf/eth?/forwarding /proc/sys/net/ipv4/conf/eth0/forwarding:0 /proc/sys/net/ipv4/conf/eth1/forwarding:1 setting ip_forward=0 and net.ipv4.conf.default.forwarding=0 and rebooting grep -v xx /proc/sys/net/ipv4/conf/eth?/forwarding /proc/sys/net/ipv4/conf/eth0/forwarding:0 /proc/sys/net/ipv4/conf/eth1/forwarding:0 # echo 1 > /proc/sys/net/ipv4/conf/default/forwarding # grep -v xx /proc/sys/net/ipv4/conf/eth?/forwarding /proc/sys/net/ipv4/conf/eth0/forwarding:0 /proc/sys/net/ipv4/conf/eth1/forwarding:0 via kernel hacker Stephen Hemminger I came to know that Default is the value used for new devices. So if you did modprobe dummy ifconfig dummy0 1.2.3.4 Then /proc/sys/net/ipv4/conf/dummy0/forwarding would be 1 IMHO, Ubuntu should thus have net.ipv4.ip_forward=1 in its /etc/sysctl.conf to let users use it as a router -- /etc/sysctl.conf should ip_forward=1 for forwarding https://launchpad.net/bugs/74129 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
