Hi,

we use modified dhclient-script and add IPv6 address with:

ip -6 addr add ${new_ip6_address}/${new_ip6_prefixlen} dev ${interface} \
     scope global valid_lft ${new_max_life} preferred_lft 
${new_preferred_life}

when I configure dhcpv6 server with infinite preferred/valid lifetime, i.e.
preferred-lifetime infinite;
default-lease-time infinite;

then I see that
$new_max_life and $new_preferred_life in dhclient-script are '-1' 
(instead of 0xffffffff).

See attached patch for fix.

With regards,
Jiri Popelka
Red Hat, inc.