To allow a FreeBSD jail to access a private network via NAT and PF, you will need to configure NAT and PF on the host system. NAT (Network Address Translation) is a mechanism that allows a jail to access the Internet through the host system's network interface. PF (Packet Filter) is a firewall that can be used to control network traffic between the jail and the Internet.
To configure NAT and PF on the host system, you will need to edit the /etc/pf.conf configuration file. You can use the following configuration as a starting point:
ext_if="em0" int_if="lo1" jail_ip="192.168.0.100" nat on $ext_if from $int_if:network to any -> ($ext_if) pass in on $ext_if inet proto tcp from any to ($ext_if) port 80 rdr-to $jail_ip
This configuration assumes that the host system has an external interface called em0 and an internal interface called lo1, and that the jail has an IP address of 192.168.0.100. The nat rule tells PF to translate the IP addresses of packets coming from the internal interface to the IP address of the external interface. The pass rule tells PF to allow incoming HTTP traffic on the external interface and redirect it to the jail.
To apply the configuration, you will need to run the following command:
pfctl -f /etc/pf.conf
This will load the configuration into the running PF instance. You can use the pfctl -s nat command to view the NAT rules that are currently in effect.
To allow the jail to access the Internet, you will need to add a default route to the jail's routing table. You can do this by running the following command in the jail:
route add default 192.168.0.1
Replace 192.168.0.1 with the IP address of the host system's internal interface. This will allow the jail to send packets to the host system, which will then be NATed and forwarded to the Internet by PF.
It is important to note that this configuration is just a starting point, and you may need to modify it to meet your specific needs. For example, you may need to allow additional ports or protocols, or you may need to block certain types of traffic. Consult the PF documentation for more information on configuring NAT and PF.