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