asterisk users - Jun 2004 - CDR not always correct / IAX clients unmonitored

We are using IAX clients and CDR logging to MySQL. It seems that sometimes calls
are not
correctly logged in the CDR db in terms of the duration of the call.

It maybe related to the fact that all peers show up as "Unmonitored"
in CLI ("iax2 show
peers").

Most (or all) our clients run behind NAT if that matters. So far I did not set
any
"qualify=XXX" value in iax.conf. When I set it to
"qualify=2000" for instance then the
status goes to "UNREACHABLE" but I can still reach my voicemail.

Any hints?

Reto