Resolve IP adresses in access.log

In order to enable ident_lookup in squid 2.1, i need to specify one DNS
serveur for my local network.
The problem is that the resolve.conf file contains the DNS servers ( one or
more ) for the internet network.
How can i do to use both internal and external DNS at the same time. Do i
have to use named ?

Thanks for the time spend on the answer..

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