I am setting up a notebook for software demo purpose. The machine has 8GB RAM, a Core i7 Intel CPU, a 128GB SSD, and runs Ubuntu 12.04 LTS 64bit. The notebook is used as a KVM host and runs a few KVM guests.
All such guests use the virbr0 default bridge. To enable them to communicate with each other using multicast, I added the following to the host's /etc/sysctl.conf, as shown below
net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0
Afterwards, following man sysctl(8), I issued the following:
sudo /sbin/sysctl -p /etc/sysctl.conf
My understanding is that this should make these settings persist over reboots. I tested it, and was surprised to find out the following:
root@sdn1 :/proc/sys/net/bridge# more *tables
::::::::::::::
bridge-nf-call-arptables
::::::::::::::
1
::::::::::::::
bridge-nf-call-ip6tables
::::::::::::::
1
::::::::::::::
bridge-nf-call-iptables
::::::::::::::
1
All defaults are coming back!
Yes. I can use some kludgy "get arounds" such as putting a /sbin/sysctl -p /etc/sysctl.conf into the host's /etc/rc.local but I would rather "do it right". Did I misunderstand the man page or is there something that I missed?
Thanks for any hints.
-- Zack
