I make another test with kernel 4.9.32-15.41 sysctl procps version 3.2.8
sysctl net.ipv4.conf.eth0.100.forwarding error: "net.ipv4.conf.eth0.100.forwarding" is an unknown key so I install busybox : BusyBox v1.19.3 busybox sysctl net.ipv4.conf.eth0.100.forwarding net.ipv4.conf.eth0.100.forwarding = 0 It is working, as I expect reading busybox source sysctl.c Stephen, I test sysctl net/ipv4/conf/eth0.100/forwarding I confirm it works. What is the problem ? As sysctl, also automation tools and scripts cannot be "netdev names aware", and so they fail using the usual dot notation. I don't pretend to change sysctl to read from the /proc/sys/ directory, as busybox does. I suggest to add a remark to the man page of sysctl, reporting the difference between the two tools and an example of the alternate syntax : sysctl net/ipv4/conf/eth0.100/forwarding Thank you for your attention. Best regards, Massimo