Read-only file system error on configuring nettwork


I’m trying to disable ipv6 editing /etc/sysctl.conf with:

sysctl: setting key "net.ipv6.conf.all.disable_ipv6 = 1

But when I try to run:
sysctl -p

I got this error:
sysctl: setting key "net.ipv6.conf.all.disable_ipv6": Read-only file system

There is other option way to disable ipv6? I trying this to resolve connection issues to a smtp.


I figured out that email ports are blocked by cloud9. =P