Comment 0 for bug 84537

Binary package hint: procps

/etc/sysctl.conf contains the following lines by default:

# Uncomment the next line to enable packet forwarding for IPv4
#net.ipv4.conf.default.forwarding=1

In my system, uncommenting the line _usually_ does the trick: IPv4 forwarding is enabled on all network interfaces. Unfortunately, this was not the case every time. Sometimes, once in 10 reboots or so, this did not work. IPv4 forwarding was not enabled on some network interfaces.

I am not 100 % sure why this happens, but I think it might be caused if sometimes a network interface gets initialised before sysctl

net.ipv4.conf.default.forwarding=1
net.ipv4.conf.all.forwarding=1

I have two physical network interfaces, "eth0" and "eth1", both of which use the "e100" driver.