##
$$href{$dn}{mail}[0];
# or
$href->{dn}{mail}[0];
# or
$href->{dn}->{mail}->[0]; ## yawn! :)
# or ...
##
##
## Make the localised glob *mail
## act as an alias to the nested array
{
local *mail = $ref->{dn}{mail};
print @mail; ## Print the whole array
print $mail[0]; ## The first element
}
## *mail reverts to it's old value here.