If you are trying to get a service running as an unprivileged user to bind to port 80 in a FreeNAS iocage jail you will need to do the following:
Set securelevel of the jail in Jail Properties to -1
Add the following two lines to /etc/sysctl.conf inside the jail:
net.inet.ip.portrange.reservedlow=0
net.inet.ip.portrange.reservedhigh=0