rc.conf

# rc.conf

# set up two bridge interfaces for iocage
cloned_interfaces="bridge0 bridge1"

# join interfaces, add the private interface to bridge0
ifconfig_bridge0="inet 10.1.1.254/24 addm vtnet1 up"

# public network
ifconfig_vtnet0="inet 37.97.135.78 netmask 255.255.255.0"

# private network
ifconfig_vtnet1="inet 192.168.1.15/24 netmask 255.255.255.0"

# routing
defaultrouter="37.97.135.78"

## IOCAGE ##

Now I run the following in iocage:

iocage create tag=foo
iocage set defaultrouter=10.1.1.254 foo
iocage set ip4_addr=10.1.1.1 foo

In iocage I can ping the router: 10.1.1.254 but I can't ping the private interface 192.168.1.15.