bind question with internal and external dns

[Carlo Corthouts]

hi,

I have an internal dns running for queries for our domain from our lan
and an external dns for queries about our domain from outside our lan
(internet).

When doing a nslookup query about our domain (domainname.zone)we get
following :

Internal dns : server.domain.zone can't find domain.zone : Non-existent
host/domain
External dns : gives correct response.

when we try looking up the webserver www.domain.zone which is behind a
firewall

Internal dns : correct response, but with a reverse lookup with IP we
get unknown.domain.zone
External dns : correct response.

What can be the reason for this?
How can we resolve the problem?

thx

carlo