PF rule question

[Darren Pilgrim]

On 10/9/2013 3:54 PM, Uroš Gruber wrote:
> Hi,
>
> I'm strugling to complete my pf firewall configuration with a bit more
> optimized rules.
>
> I have a few hudreds jails set up on network from 172.16.1.0 to 172.16.10.0
>
> My goal is to deny access between jails, but allow a few exceptions for
> example all jails can connect to jails from 172.16.1.0 to 172.16.1.64.
>
> I've accomplished this with rules like
>
> pass on lo0 from $jailnet to 172.16.1.0/26
> pass on lo0 from 172.16.1.1 to 172.16.1.1
>
> I would like to know if there is a better way to write such rules mostly
> because all that jails are very dynamic in terms of
> runing,stoping/destroying etc. and also IP aliases are removed and added
> back continuously.

Use an anchor for the "pass on lo0 from X to X" rules and a table for 
the jailnet.  Then have your jail provisioning scripts manipulate the 
table and anchor as jails come up and down.

In /etc/pf.conf:

	table <jailnet> persist
	pass on lo0 from <jailnet> to 172.16.1.0/26
	anchor <jails>

When bringing up a jail:

# pfctl -t jailnet -T add 192.0.2.65
# pfctl -a jails -f - <<<"pass on lo0 from 192.0.2.65 to 192.0.2.65"

When taking down a jail:

# pfctl -t jailnet -T delete 192.0.2.65
# pfctl -a jails -f - <<<"block on lo0 from 192.0.2.65 to 192.0.2.65"
# pfctl -k 192.0.2.65

You'll need to reload the table and anchor rules on a system restart. 
You can do that with rules in /etc/pf.conf:

	table <jailnet> persist /path/to/jailnet_address_list
	load anchor jails from /path/to/jails_rules_list

or directly using pfctl:

# pfctl -t jailnet -Ta -f /path/to/jailnet_address_list
# pfctl -a jails -f /path/to/jails_rules_list