HINT: вырубить сообщения iptables в текстовой консоле (Fedora)

dmesg -n

и

setterm -msglevel

но, по-моему, это через одно место.

The  console  log  level  is  usually configured with the sysctl(8)
program, directly or via its configuration file /etc/sysctl.conf.
In this file the following line

  kernel.printk = 4 4 1 7

corresponds to the sampe setting above.