I have a problem with a jail trying to update and install gems from rubygem.org. Apparently this is some problem with IPv6. The Gem utility is reported to prefe IPv6 if it is available. I would like to configure the jail to only use ipv4 and avoid this if this turns out to be the problem. The jail is configured only with an IPv4 address. The Host has IPv6 enabled. I have looked at ail(8) and rc.conf(5) but cannot find a switch or parameter that turns ipv6 off. How does one turn off ipv6 in a jail without impacting the host?