chaching is possible on dns-ldap?

[S Kalyanasundaram]

Is there any caching planned on dns-ldap integration ? For every query
made to dns is making an access to LDAP server.  I feel really a
performance hit here. In case if the ldap server is down DNS server wont
be able to perform any query resolution in this case.
But i guess caching is simply not possible, there has to be something
more to do with the sdb drivers of bind.

-"kalyan"