Si, si può fare anche se di solito si vuole evitare per semplificare la gestione delle jails. Tutto senza impostare nessun reverse proxy.
Se guardi la documentazione riguardo alle jail nella parte in cui si parla della configurazione della rete troverai dettagli (bridge ethernet).
sei certo che si possa fare? In realtà che io sappia il "bridge" serve appunto per associare network virtuali con differenti indirizzi al network fisico della macchina su cui è installato FN...
"The IPv4 and IPv6 bridge interface is used to bridge the
epair(4) device, which is automatically created for each started jail, to a physical network device. The default network device is the one that is configured with a default gateway. So, if
em0 is the FreeBSD name of the physical interface and three jails are running, these virtual interfaces are automatically created:
bridge0,
epair0a,
epair1a, and
epair2a. The physical interface
em0 will be added to the bridge, as well as each epair device. The other half of the epair will be placed inside the jail and will be assigned the IP address specified for that jail. The bridge interface will be assigned an alias of the default gateway for that jail, if configured, or the bridge IP, if configured; either is correct.
The only time an IP address and mask are required for the bridge is when the jail will be on a different network than the FreeNAS® system. For example, if the FreeNAS® system is on the
10.0.0.0/24 network and the jail will be on the
192.168.0.0/24 network, set the IPv4 bridge address and IPv4 bridge netmask fields for the jail."
http://doc.freenas.org/11/jails.html#jails-configuration