if you obtain:

ping: socket: Operation not permitted

although:

 security.jail.allow_raw_sockets=1

is set in /etc/sysctl.conf
you should add an option in the rc.conf

jail_yourjailname_parameters="allow.raw_sockets=1"

or add this option in /etc/jail.conf if you are using new configuration scheme added in FreeBSD 9.1 – see man jail.conf