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On Debian 12.04 LTS
I am trying to access the key net.ipv4.conf.all.mc_forwarding by doing :
sudo sysctl -w net.ipv4.conf.all.mc_forwarding=1
But every time I am doing this, I get the message
error: permission denied on key 'net.ipv4.conf.all.mc_forwarding'
Why do I get this message? How can I change this key?
I believe this thread describes your problem
In a nutshell, the proc entry containing that value is read-only, and cannot be made writable easily:
$ ls -ln /proc/sys/net/ipv4/conf/all/mc_forwarding
-r--r--r-- 1 0 0 0 Jun 17 08:20 /proc/sys/net/ipv4/conf/all/mc_forwarding
$ sudo chmod u+x /proc/sys/net/ipv4/conf/all/mc_forwarding
chmod: changing permissions of `/proc/sys/net/ipv4/conf/all/mc_forwarding': Operation not permitted
But you can run your own router daemon to (e.g xorp) to get multicast forwarding.
you can also get error like this sysctl: setting key "net.ipv4.conf.all.mc_forwarding": No such file or directory
mc_forwarding - BOOLEAN
Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE
and a multicast routing daemon is required.
conf/all/mc_forwarding must also be set to TRUE to enable multicast
routing for the interface
kernel should be compiled with option CONFIG_MROUTE, default kernel is not have this option set.
