Got DNS working again on this server by manually downgrading bind9 to 9.5.1 (9.5.1.dfsg.P2-1+lenny1). Downloaded and dpkg -i the following packages (apt-get install pkg=version didn't find them):
bind9 bind9utils bind9-host dnsutils The problem with 9.6.1 seems to be the bindings in libbind9-50.
